diff --git a/.github/workflows/build-complete-samples.yml b/.github/workflows/build-complete-samples.yml
index 99a0d27e4b..5f4d08064c 100644
--- a/.github/workflows/build-complete-samples.yml
+++ b/.github/workflows/build-complete-samples.yml
@@ -496,6 +496,10 @@ jobs:
               name: 'bot-auth0-adaptivecard'
               version: '6.0.x'
 
+            - project_path: 'samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/TabAuthEntraAccount.csproj'
+              name: 'tab-auth-entra-account'
+              version: '6.0.x'
+
       fail-fast: false
     name: Build All "${{ matrix.name }}" csharp
     steps:
diff --git a/README.md b/README.md
index 2e0f0acce5..d82d4fef08 100644
--- a/README.md
+++ b/README.md
@@ -76,7 +76,7 @@ The [Teams Toolkit](https://marketplace.visualstudio.com/items?itemName=TeamsDev
 | 24 | Tab External Auth                          | This sample illustrates how to implement Google auth using external auth providers.                                                                                                                                               | Advanced     | [View][tab-external-auth#csharp]       |                                             |                                             |                                                                    |
 | 25 | Nested App Authentication                  | This sample shows nested app authentication (NAA), a new protocol that simplifies single sign-on (SSO) for single-page applications.                                           | Advanced     | [View][tab-nested-auth#cs]             | [View][tab-nested-auth#nodejs] ![toolkit-icon](assets/toolkit-icon.png) |               |[View](/samples/tab-nested-auth/csharp/demo-manifest/tab-nested-auth.zip) |                                            |                                                                    |
 | 26 | Tab Meeting Recording and transcript with auto recording | This sample shows meeting recording and transcript with auto recording.                                                                                                         | Advanced     | [View][tab-meeting-auto-recording#csharp] |                                             |                                             |                                                                    |
-| 27 | Tab External Auth                          | This sample illustrates how to implement Google auth using external auth providers.                                                                                                                                               | Advanced     | [View][tab-external-auth#csharp]       |                                             |                                             |                                                                    |
+| 27 | Sign in using a different Microsoft Entra account                          | Teams tab sample showing auth and account switching with Entra ID.                                                                                                                                               | Advanced     | [View][tab-auth-entra-account#csharp]       |                                             |                                             |                                                                    |
 | 28 | Tab Meeting Recording and transcript with auto recording | This sample shows meeting recording and transcript with auto recording.                                                                                                         | Advanced     | [View][tab-meeting-auto-recording#csharp] |                                             |                                             |                                                                    |
 ## [Bots samples](https://docs.microsoft.com/microsoftteams/platform/bots/what-are-bots) (using the v4 SDK)
 >NOTE:
@@ -300,6 +300,7 @@ The [Teams Toolkit](https://marketplace.visualstudio.com/items?itemName=TeamsDev
 [tab-multi-hub#ts]:samples/tab-multi-hub/ts
 [tab-ui-templates#ts]:samples/tab-ui-templates/ts
 [tab-external-auth#csharp]:samples/tab-external-auth/csharp
+[tab-auth-entra-account#csharp]:samples/tab-auth-entra-account/csharp
 [tab-meeting-transcript-recording#nodejs]:samples/tab-meeting-transcript-recording/nodejs
 [tab-meeting-transcript-recording#csharp]:samples/tab-meeting-transcript-recording/csharp
 [tab-adhoccalls-transcript-recording#nodejs]:samples/tab-adhoccalls-transcript-recording/nodejs
diff --git a/samples/tab-auth-entra-account/csharp/Images/1.DesktopInstallApp.png b/samples/tab-auth-entra-account/csharp/Images/1.DesktopInstallApp.png
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diff --git a/samples/tab-auth-entra-account/csharp/Images/11.OfficeLoginPage.png b/samples/tab-auth-entra-account/csharp/Images/11.OfficeLoginPage.png
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diff --git a/samples/tab-auth-entra-account/csharp/Images/12.OfficeLoginUserDetails.png b/samples/tab-auth-entra-account/csharp/Images/12.OfficeLoginUserDetails.png
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diff --git a/samples/tab-auth-entra-account/csharp/Images/2.DesktopLoginPage.png b/samples/tab-auth-entra-account/csharp/Images/2.DesktopLoginPage.png
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diff --git a/samples/tab-auth-entra-account/csharp/Images/3.DesktopClickLogin.png b/samples/tab-auth-entra-account/csharp/Images/3.DesktopClickLogin.png
new file mode 100644
index 0000000000..b5357b05f5
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diff --git a/samples/tab-auth-entra-account/csharp/Images/4.DesktopEnterAccount.png b/samples/tab-auth-entra-account/csharp/Images/4.DesktopEnterAccount.png
new file mode 100644
index 0000000000..baca44878b
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diff --git a/samples/tab-auth-entra-account/csharp/Images/5.DesktopLoginUserDetails.png b/samples/tab-auth-entra-account/csharp/Images/5.DesktopLoginUserDetails.png
new file mode 100644
index 0000000000..82f6e17d0b
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diff --git a/samples/tab-auth-entra-account/csharp/Images/6.OutlookSelectApp.png b/samples/tab-auth-entra-account/csharp/Images/6.OutlookSelectApp.png
new file mode 100644
index 0000000000..06d56a85cb
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diff --git a/samples/tab-auth-entra-account/csharp/Images/7.OutlookLoginPage.png b/samples/tab-auth-entra-account/csharp/Images/7.OutlookLoginPage.png
new file mode 100644
index 0000000000..adce2edca9
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diff --git a/samples/tab-auth-entra-account/csharp/Images/8.OutlookLoginUserDetails.png b/samples/tab-auth-entra-account/csharp/Images/8.OutlookLoginUserDetails.png
new file mode 100644
index 0000000000..49037a8f09
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diff --git a/samples/tab-auth-entra-account/csharp/Images/9.OfficeSelectApp.png b/samples/tab-auth-entra-account/csharp/Images/9.OfficeSelectApp.png
new file mode 100644
index 0000000000..2eb73cf216
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diff --git a/samples/tab-auth-entra-account/csharp/Images/tab-auth-entra-accountGIF.gif b/samples/tab-auth-entra-account/csharp/Images/tab-auth-entra-accountGIF.gif
new file mode 100644
index 0000000000..cc129b6106
Binary files /dev/null and b/samples/tab-auth-entra-account/csharp/Images/tab-auth-entra-accountGIF.gif differ
diff --git a/samples/tab-auth-entra-account/csharp/M365Agent/M365Agent.ttkproj b/samples/tab-auth-entra-account/csharp/M365Agent/M365Agent.ttkproj
new file mode 100644
index 0000000000..1086814a87
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/M365Agent/M365Agent.ttkproj
@@ -0,0 +1,13 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" Sdk="Microsoft.TeamsFx.Sdk">
+  <PropertyGroup Label="Globals">
+    <ProjectGuid>42a0237c-30e0-42ae-b6ed-50f318517e77</ProjectGuid>
+  </PropertyGroup>
+  <ItemGroup>
+    <None Include="m365agents.local.yml" />
+    <None Include="m365agents.yml" />
+  </ItemGroup>
+  <ItemGroup>
+    <ProjectCapability Include="ProjectConfigurationsDeclaredDimensions" />
+  </ItemGroup>
+</Project>
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/M365Agent/aad.manifest.json b/samples/tab-auth-entra-account/csharp/M365Agent/aad.manifest.json
new file mode 100644
index 0000000000..e827fbea85
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/M365Agent/aad.manifest.json
@@ -0,0 +1,50 @@
+{
+  "id": "${{AAD_APP_OBJECT_ID}}",
+  "appId": "${{AAD_APP_CLIENT_ID}}",
+  "displayName": "tab-auth-entra-account-aad",
+  "signInAudience": "AzureADMultipleOrgs",
+  "api": {
+    "requestedAccessTokenVersion": 2
+  },
+  "info": {},
+  "optionalClaims": {
+    "idToken": [],
+    "accessToken": [
+      {
+        "name": "idtyp",
+        "source": null,
+        "essential": false,
+        "additionalProperties": []
+      }
+    ],
+    "saml2Token": []
+  },
+  "publicClient": {
+    "redirectUris": []
+  },
+  "requiredResourceAccess": [
+    {
+      "resourceAppId": "00000003-0000-0000-c000-000000000000",
+      "resourceAccess": [
+        {
+          "id": "e1fe6dd8-ba31-4d61-89e7-88639da4683d",
+          "type": "Scope"
+        }
+      ]
+    }
+  ],
+  "web": {
+    "redirectUris": [],
+    "implicitGrantSettings": {
+      "enableAccessTokenIssuance": true,
+      "enableIdTokenIssuance": true
+    }
+  },
+  "spa": {
+    "redirectUris": [
+      "${{BOT_ENDPOINT}}/Auth/AuthStart",
+      "${{BOT_ENDPOINT}}/Auth/AuthEnd"
+    ]
+  },
+  "isFallbackPublicClient": true
+}
diff --git a/samples/tab-auth-entra-account/csharp/M365Agent/appPackage/color.png b/samples/tab-auth-entra-account/csharp/M365Agent/appPackage/color.png
new file mode 100644
index 0000000000..b8cf81afbe
Binary files /dev/null and b/samples/tab-auth-entra-account/csharp/M365Agent/appPackage/color.png differ
diff --git a/samples/tab-auth-entra-account/csharp/M365Agent/appPackage/manifest.json b/samples/tab-auth-entra-account/csharp/M365Agent/appPackage/manifest.json
new file mode 100644
index 0000000000..1f0e9e1f41
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/M365Agent/appPackage/manifest.json
@@ -0,0 +1,38 @@
+{
+  "$schema": "https://developer.microsoft.com/json-schemas/teams/v1.19/MicrosoftTeams.schema.json",
+  "manifestVersion": "1.19",
+  "version": "1.0.0",
+  "id": "${{TEAMS_APP_ID}}",
+  "developer": {
+    "name": "Microsoft",
+    "websiteUrl": "https://www.microsoft.com",
+    "privacyUrl": "https://www.microsoft.com/privacy",
+    "termsOfUseUrl": "https://www.microsoft.com/termsofuse"
+  },
+  "name": {
+    "short": "Tab Auth Entra Accounts",
+    "full": "Sign in using a different Microsoft Entra account"
+  },
+  "description": {
+    "short": "Teams tab sample showing auth and account switching with Entra ID.",
+    "full": "This Microsoft Teams tab sample demonstrates how to integrate Microsoft Entra ID (Azure AD) authentication. It allows users to sign in and switch between different Entra accounts for secure, flexible access. Use a different Entra account to sign in to the application."
+  },
+  "icons": {
+    "outline": "outline.png",
+    "color": "color.png"
+  },
+  "accentColor": "#60A18E",
+  "staticTabs": [
+    {
+      "entityId": "auth",
+      "name": "Auth",
+      "contentUrl": "https://${{BOT_DOMAIN}}/Home/Index",
+      "scopes": [
+        "personal"
+      ]
+    }
+  ],
+  "validDomains": [
+    "${{BOT_DOMAIN}}"
+  ]
+}
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/M365Agent/appPackage/outline.png b/samples/tab-auth-entra-account/csharp/M365Agent/appPackage/outline.png
new file mode 100644
index 0000000000..2c3bf6fa65
Binary files /dev/null and b/samples/tab-auth-entra-account/csharp/M365Agent/appPackage/outline.png differ
diff --git a/samples/tab-auth-entra-account/csharp/M365Agent/env/.env.local b/samples/tab-auth-entra-account/csharp/M365Agent/env/.env.local
new file mode 100644
index 0000000000..97e4be597f
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/M365Agent/env/.env.local
@@ -0,0 +1,27 @@
+# This file includes environment variables that can be committed to git. It's gitignored by default because it represents your local development environment.
+
+# Built-in environment variables
+TEAMSFX_ENV=local
+
+# Generated during provision, you can also add your own variables. 
+TEAMS_APP_ID=
+AAD_APP_CLIENT_ID=
+AAD_APP_OBJECT_ID=
+AAD_APP_OAUTH2_PERMISSION_ID=
+AAD_APP_TENANT_ID=
+AAD_APP_OAUTH_AUTHORITY_HOST=
+AAD_APP_OAUTH_AUTHORITY=
+TAB_ENDPOINT=
+
+
+
+
+APP_NAME_SUFFIX=
+TAB_DOMAIN=
+TEAMS_APP_TENANT_ID=
+M365_TITLE_ID=
+M365_APP_ID=
+TEAMSFX_M365_USER_NAME=
+
+BOT_ENDPOINT=
+BOT_DOMAIN=
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/M365Agent/launchSettings.json b/samples/tab-auth-entra-account/csharp/M365Agent/launchSettings.json
new file mode 100644
index 0000000000..49d554e6c3
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/M365Agent/launchSettings.json
@@ -0,0 +1,23 @@
+{
+	"profiles": {
+		// Debug project within Teams
+		"Microsoft Teams (browser)": {
+			"commandName": "Project",
+			"launchUrl": "https://teams.microsoft.com/l/app/${{TEAMS_APP_ID}}?installAppPackage=true&webjoin=true&appTenantId=${{TEAMS_APP_TENANT_ID}}&login_hint=${{TEAMSFX_M365_USER_NAME}}"
+		},
+		"Outlook (browser)": {
+			"commandName": "Project",
+			"launchUrl": "https://outlook.office.com/host/${{M365_APP_ID}}?login_hint=${{TEAMSFX_M365_USER_NAME}}"
+		},
+		"Microsoft 365 app (browser)": {
+			"commandName": "Project",
+			"launchUrl": "https://www.office.com/m365apps/${{M365_APP_ID}}?auth=2&login_hint=${{TEAMSFX_M365_USER_NAME}}"
+		},
+		// Launch project within Teams without prepare app dependencies
+		"Microsoft Teams (browser) (skip update app)": {
+			"commandName": "Project",
+			"environmentVariables": { "UPDATE_TEAMS_APP": "false" },
+			"launchUrl": "https://teams.microsoft.com/l/app/${{TEAMS_APP_ID}}?installAppPackage=true&webjoin=true&appTenantId=${{TEAMS_APP_TENANT_ID}}&login_hint=${{TEAMSFX_M365_USER_NAME}}"
+		}
+	}
+}
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/M365Agent/m365agents.local.yml b/samples/tab-auth-entra-account/csharp/M365Agent/m365agents.local.yml
new file mode 100644
index 0000000000..e3e4b9457f
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/M365Agent/m365agents.local.yml
@@ -0,0 +1,103 @@
+# yaml-language-server: $schema=https://aka.ms/teams-toolkit/v1.8/yaml.schema.json
+# Visit https://aka.ms/teamsfx-v5.0-guide for details on this file
+# Visit https://aka.ms/teamsfx-actions for details on actions
+version: v1.8
+
+additionalMetadata:
+  sampleTag: Microsoft-Teams-Samples:tab-auth-entra-account-csharp
+
+provision:
+  # Creates a new Azure Active Directory (AAD) app to authenticate users if
+  # the environment variable that stores clientId is empty
+  - uses: aadApp/create
+    with:
+      # Note: when you run aadApp/update, the AAD app name will be updated
+      # based on the definition in manifest. If you don't want to change the
+      # name, make sure the name in AAD manifest is the same with the name
+      # defined here.
+      name: tab-auth-entra-account-aad
+      # If the value is false, the action will not generate client secret for you
+      generateClientSecret: true
+      # Authenticate users with a Microsoft work or school account in your
+      # organization's Azure AD tenant (for example, single tenant).
+      signInAudience: AzureADMultipleOrgs
+    # Write the information of created resources into environment file for the
+    # specified environment variable(s).
+    writeToEnvironmentFile:
+      clientId: AAD_APP_CLIENT_ID
+      # Environment variable that starts with `SECRET_` will be stored to the
+      # .env.{envName}.user environment file
+      clientSecret: SECRET_AAD_APP_CLIENT_SECRET
+      objectId: AAD_APP_OBJECT_ID
+      tenantId: AAD_APP_TENANT_ID
+      authority: AAD_APP_OAUTH_AUTHORITY
+      authorityHost: AAD_APP_OAUTH_AUTHORITY_HOST
+
+  # Set TAB_DOMAIN and TAB_ENDPOINT for local launch
+  - uses: script
+    with:
+      run: echo "::set-teamsfx-env TAB_DOMAIN=localhost:44302"; echo
+        "::set-teamsfx-env TAB_ENDPOINT=https://localhost:44302";
+
+  # Creates a Teams app
+  - uses: teamsApp/create
+    with:
+      # Teams app name
+      name: tab-auth-entra-account-${{TEAMSFX_ENV}}
+    # Write the information of created resources into environment file for
+    # the specified environment variable(s).
+    writeToEnvironmentFile:
+      teamsAppId: TEAMS_APP_ID
+
+  # Generate runtime appsettings to JSON file
+  - uses: file/createOrUpdateJsonFile
+    with:
+      target: ../TabAuthEntraAccount/appsettings.json
+      content:
+        AzureAd:
+          ClientId: ${{AAD_APP_CLIENT_ID}}
+          RedirectUri: https://${{BOT_DOMAIN}}/Auth/AuthEnd
+
+  # Apply the AAD manifest to an existing AAD app. Will use the object id in
+  # manifest file to determine which AAD app to update.
+  - uses: aadApp/update
+    with:
+      # Relative path to this file. Environment variables in manifest will
+      # be replaced before apply to AAD app
+      manifestPath: ./aad.manifest.json
+      outputFilePath: ./build/aad.manifest.${{TEAMSFX_ENV}}.json
+
+  # Validate using manifest schema
+  - uses: teamsApp/validateManifest
+    with:
+      # Path to manifest template
+      manifestPath: ./appPackage/manifest.json
+  # Build Teams app package with latest env value
+  - uses: teamsApp/zipAppPackage
+    with:
+      # Path to manifest template
+      manifestPath: ./appPackage/manifest.json
+      outputZipPath: ./appPackage/build/appPackage.${{TEAMSFX_ENV}}.zip
+      outputFolder: ./appPackage/build
+  # Validate app package using validation rules
+  - uses: teamsApp/validateAppPackage
+    with:
+      # Relative path to this file. This is the path for built zip file.
+      appPackagePath: ./appPackage/build/appPackage.${{TEAMSFX_ENV}}.zip
+  # Apply the Teams app manifest to an existing Teams app in
+  # Developer Portal.
+  # Will use the app id in manifest file to determine which Teams app to update.
+  - uses: teamsApp/update
+    with:
+      # Relative path to this file. This is the path for built zip file.
+      appPackagePath: ./appPackage/build/appPackage.${{TEAMSFX_ENV}}.zip
+  # Extend your Teams app to Outlook and the Microsoft 365 app
+  - uses: teamsApp/extendToM365
+    with:
+      # Relative path to the build app package.
+      appPackagePath: ./appPackage/build/appPackage.${{TEAMSFX_ENV}}.zip
+    # Write the information of created resources into environment file for
+    # the specified environment variable(s).
+    writeToEnvironmentFile:
+      titleId: M365_TITLE_ID
+      appId: M365_APP_ID
diff --git a/samples/tab-auth-entra-account/csharp/M365Agent/m365agents.yml b/samples/tab-auth-entra-account/csharp/M365Agent/m365agents.yml
new file mode 100644
index 0000000000..b70ad541ac
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/M365Agent/m365agents.yml
@@ -0,0 +1,9 @@
+# yaml-language-server: $schema=https://aka.ms/teams-toolkit/v1.8/yaml.schema.json
+# Visit https://aka.ms/teamsfx-v5.0-guide for details on this file
+# Visit https://aka.ms/teamsfx-actions for details on actions
+version: v1.8
+
+additionalMetadata:
+  sampleTag: Microsoft-Teams-Samples:tab-auth-entra-account-csharp
+
+environmentFolderPath: ./env
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/README.md b/samples/tab-auth-entra-account/csharp/README.md
new file mode 100644
index 0000000000..ffad8c0581
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/README.md
@@ -0,0 +1,252 @@
+---
+page_type: sample
+description: This sample app demonstrates the integration of Microsoft Entra ID (Azure AD) for user authentication within Microsoft Teams. It features a tab-based interface that allows users to sign in and switch between different Entra accounts for secure, flexible access.
+products:
+- office-teams
+- office
+- office-365
+languages:
+- csharp
+extensions:
+ contentType: samples
+ createdDate: "25/07/2025 11:20:17 AM"
+urlFragment: officedev-microsoft-teams-samples-tab-auth-entra-account-csharp
+---
+# Sign in using a different Microsoft Entra account - C# (PKCE Flow)
+
+This Microsoft Teams sample app illustrates how to integrate Microsoft Entra ID (Azure AD) authentication in a Teams tab using the **OAuth 2.0 Authorization Code Flow with PKCE (Proof Key for Code Exchange)**. This implementation provides a **client-side only** authentication solution that enables users to sign in and switch between different Entra accounts.
+
+## Included Features
+* External Auth
+* Tabs
+* Microsoft Entra ID Integration
+* Account Switching
+* Cross-platform Support (Teams, Outlook, Office)
+
+## Interaction with app
+
+![tab-auth-entra-accountGIF](Images/tab-auth-entra-accountGIF.gif)
+
+## Authentication Flow Diagram
+
+The following diagram illustrates the Microsoft Entra ID authentication flow using OAuth 2.0 Authorization Code Flow with PKCE (Proof Key for Code Exchange) - a client-side only implementation suitable for Single Page Applications:
+
+```mermaid
+sequenceDiagram
+    participant U as User
+    participant T as Teams Tab (JavaScript)
+    participant E as Microsoft Entra ID
+    participant API as Microsoft Graph API
+
+    Note over U,API: PKCE Authentication Flow for Teams Tab with Entra ID
+
+    U->>T: Opens Teams Tab
+    T->>U: Displays authentication page
+    
+    U->>T: Clicks "Sign In" button
+    T->>T: Generate PKCE code verifier & challenge
+    T->>E: Redirect to Entra ID authorization endpoint with PKCE
+    Note right of E: OAuth 2.0 Authorization Code Flow with PKCE
+    
+    E->>U: Display Entra ID login page
+    U->>E: Enter credentials & consent
+    E->>T: Redirect with authorization code
+    T->>E: Exchange code for access token using PKCE
+    E->>T: Return access token & refresh token
+    
+    Note over T,API: Authenticated User Session (Client-side only)
+    T->>API: API calls with access token
+    API->>T: Return user data/resources
+    T->>U: Display authenticated content
+    
+    Note over U,T: Account Switching
+    U->>T: Click "Switch Account"
+    T->>E: Re-initiate PKCE auth flow with different account
+    E->>U: Account selection/login page
+    U->>E: Select different account
+    E->>T: New access token for different account
+```
+## Prerequisites
+
+- [.NET Core SDK](https://dotnet.microsoft.com/download) version 6.0
+
+  To determine your dotnet version:
+  ```bash
+  dotnet --version
+  ```
+- [dev tunnel](https://learn.microsoft.com/en-us/azure/developer/dev-tunnels/get-started?tabs=windows) or [Ngrok](https://ngrok.com/download) (For local environment testing) latest version (any other tunneling software can also be used)
+  
+- [Teams](https://teams.microsoft.com) Microsoft Teams is installed and you have an account
+
+- [Microsoft 365 Agents Toolkit for Visual Studio](https://learn.microsoft.com/en-us/microsoftteams/platform/toolkit/toolkit-v4/install-teams-toolkit-vs?pivots=visual-studio-v17-7)
+
+## Run the app (Using Microsoft 365 Agents Toolkit for Visual Studio)
+
+The simplest way to run this sample in Teams is to use Microsoft 365 Agents Toolkit for Visual Studio.
+
+1. Install Visual Studio 2022 **Version 17.14 or higher** [Visual Studio](https://visualstudio.microsoft.com/downloads/)
+1. Install Microsoft 365 Agents Toolkit for Visual Studio [Microsoft 365 Agents Toolkit extension](https://learn.microsoft.com/en-us/microsoftteams/platform/toolkit/toolkit-v4/install-teams-toolkit-vs?pivots=visual-studio-v17-7)
+1. In the debug dropdown menu of Visual Studio, select Dev Tunnels > Create A Tunnel (set authentication type to Public) or select an existing public dev tunnel.
+1. Right-click the 'M365Agent' project in Solution Explorer and select **Microsoft 365 Agents Toolkit > Select Microsoft 365 Account**
+1. Sign in to Microsoft 365 Agents Toolkit with a **Microsoft 365 work or school account**
+1. Set `Startup Item` as `Microsoft Teams (browser)`.
+1. Press F5, or select Debug > Start Debugging menu in Visual Studio to start your app
+</br>![image](https://raw.githubusercontent.com/OfficeDev/TeamsFx/dev/docs/images/visualstudio/debug/debug-button.png)
+1. In the opened web browser, select Add button to install the app in Teams
+
+> If you do not have permission to upload custom apps (uploading), Microsoft 365 Agents Toolkit will recommend creating and using a Microsoft 365 Developer Program account - a free program to get your own dev environment sandbox that includes Teams.
+
+## Setup
+1. Register a new application in the [Microsoft Entra ID – App Registrations](https://go.microsoft.com/fwlink/?linkid=2083908) portal.
+
+  - Select **New Registration** and on the *register an application page*, set following values:
+     * Set **name** to your app name.
+     * Choose the **supported account types** (any account type will work)
+     * Leave **Redirect URI** empty.
+     * Choose **Register**.
+  - On the overview page, copy and save the **Application (client) ID, Directory (tenant) ID**. You'll need those later when updating your Teams application manifest and in the appsettings.json.
+  
+  - Navigate to **Authentication**
+    If an app hasn't been granted IT admin consent, users will have to provide consent the first time they use an app.
+    
+    **Configure for Single Page Application (SPA) with PKCE:**
+    * Select **Add a platform**.
+    * Select **Single-page application**.
+    * Enter the **redirect URI** for the app in the following format: 
+         * https://<your_tunnel_domain>/Auth/AuthEnd, 
+         * https://<your_tunnel_domain>/Auth/AuthStart. 
+      This will be the page where a successful authorization code flow will redirect the user.
+    
+    **Enable implicit grant flows (for backward compatibility):**
+    ✔ ID Token  
+    ✔ Access Token
+    
+    **Allow public client flows:** Set to **Yes**
+  
+  - Navigate to the **Certificates & secrets**. 
+    **Note:** For PKCE flow, client secrets are **not required** and **not recommended** for security reasons.
+    However, if you need them for other purposes, you can still create them:
+    In the Client secrets section, click on "+ New client secret". Add a description (Name of the secret) for the secret and select "Never" for Expires. Click "Add". Once the client secret is created, copy its value, it need to be placed in the appsettings.json.
+
+2. Setup Development Tunnel (NGROK or Dev Tunnel)
+- Run ngrok - point to port 3978
+
+```bash
+   ngrok http 3978 --host-header="localhost:3978"
+   ```  
+
+   Alternatively, you can also use the `dev tunnel`. Please follow [Create and host a Dev tunnel](https://learn.microsoft.com/en-us/azure/developer/dev-tunnels/get-started?tabs=windows) and host the tunnel with anonymous user access command as shown below:
+
+   ```bash
+   devtunnel host -p 3978 --allow-anonymous
+   ```
+
+3. Setup for code
+
+- Clone the repository
+
+    ```bash
+    git clone https://github.com/OfficeDev/Microsoft-Teams-Samples.git
+    ```
+
+- Navigate to the sample directory
+    ```bash
+    cd samples/tab-auth-entra-account/csharp
+    ```
+
+- Modify the `TabAuthEntraAccount/appsettings.json` and fill in the following details:
+  - `{{AzureAd:ClientId}}` - Generated from Step 1 while doing Microsoft Entra ID app registration in Azure portal.
+  - `{{AzureAd:RedirectUri}}` - Your Redirect URI. ex: `https://%ngrokDomain%.ngrok-free.app/Auth/AuthEnd`
+
+- If you are using Visual Studio
+  - Launch Visual Studio
+  - File -> Open -> Project/Solution
+  - Navigate to `/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount` folder
+  - Select `TabAuthEntraAccount.csproj` file
+
+4. Setup Manifest for Teams App
+    - **Edit** the `M365Agent/appPackage/manifest.json` contained in the ./M365Agent/appPackage folder to replace placeholder `{{BOT_DOMAIN}}` with your tunnel domain. E.g. if you are using ngrok it would be `1234.ngrok-free.app` and if you are using dev tunnel, your domain will be `12345.devtunnels.ms`.
+    - **Edit** the `manifest.json` for `validDomains` and replace `{{domain-name}}` with base Url of your domain. E.g. if you are using ngrok it would be `https://1234.ngrok-free.app` then your domain-name will be `1234.ngrok-free.app`. And if you are using dev tunnel, your URL will be https://12345.devtunnels.ms.
+    - **Zip** up the contents of the `M365Agent/appPackage` folder to create a `manifest.zip` (Make sure that zip file does not contains any subfolder otherwise you will get error while uploading your .zip package)
+
+- Upload the manifest.zip to Teams (in the Apps view click "Upload a custom app")
+   - Go to Microsoft Teams. From the lower left corner, select Apps
+   - From the lower left corner, choose Upload a custom App
+   - Go to your project directory, the ./M365Agent/appPackage folder, select the zip folder, and choose Open.
+   - Select Add in the pop-up dialog box. Your app is uploaded to Teams.
+
+## Running the sample
+
+**Note:** 
+* **Supported Platforms:**
+  - Microsoft Teams – Desktop and Web
+  - Microsoft Outlook – Desktop and Web  
+  - Microsoft Office – Desktop and Web
+
+* **Not Supported:**
+  - Microsoft Teams, Outlook, and Office – Mobile applications
+
+## Microsoft Teams
+
+#### Step 1: Installing the tab authentication app in Microsoft Teams desktop client
+![DesktopInstallApp](Images/1.DesktopInstallApp.png)
+
+#### Step 2: The initial authentication page displayed when accessing the app in Teams
+![DesktopLoginPage](Images/2.DesktopLoginPage.png)
+
+#### Step 3: User clicking the login button to initiate Microsoft Entra ID authentication
+![DesktopClickLogin](Images/3.DesktopClickLogin.png)
+
+#### Step 4: Microsoft Entra ID login screen where user enters their account credentials
+![DesktopEnterAccount](Images/4.DesktopEnterAccount.png)
+
+#### Step 5: Successfully authenticated user's profile information displayed in the Teams tab
+![DesktopLoginUserDetails](Images/5.DesktopLoginUserDetails.png)
+
+## Microsoft Outlook
+
+- To view your app in Outlook on the desktop.
+
+#### Step 1: Selecting the tab authentication app from the Outlook desktop client app gallery
+![OutlookSelectApp](Images/6.OutlookSelectApp.png)
+
+#### Step 2: The authentication interface displayed when accessing the app within Outlook
+![OutlookLoginPage](Images/7.OutlookLoginPage.png)
+
+#### Step 3: Successfully authenticated user's profile information displayed in the Outlook tab
+![OutlookLoginUserDetails](Images/8.OutlookLoginUserDetails.png)
+
+## Microsoft Office
+
+- To preview your app running in Office on the desktop.
+
+#### Step 1: Selecting the tab authentication app from the Microsoft Office desktop client
+![OfficeSelectApp](Images/9.OfficeSelectApp.png)
+
+#### Step 2: Installing the tab authentication app in Microsoft Office desktop client
+![OfficeInstallApp](Images/10.OfficeInstallApp.png)
+
+#### Step 3: The authentication interface displayed when accessing the app within Microsoft Office
+![OfficeLoginPage](Images/11.OfficeLoginPage.png)
+
+#### Successfully authenticated user's profile information displayed in the Microsoft Office tab
+![OfficeLoginUserDetails](Images/12.OfficeLoginUserDetails.png)
+
+## Further Reading
+
+#### Authentication and Microsoft Entra ID
+- [External authentication in Microsoft Teams](https://learn.microsoft.com/microsoftteams/platform/tabs/how-to/authentication/auth-oauth-provider#add-authentication-to-external-browsers)
+- [Microsoft Entra ID authentication in Teams apps](https://learn.microsoft.com/en-us/microsoftteams/platform/tabs/how-to/authentication/auth-aad-sso)
+- [OAuth 2.0 authorization code flow](https://learn.microsoft.com/en-us/azure/active-directory/develop/v2-oauth2-auth-code-flow)
+
+#### Microsoft Teams Development
+- [Teams app manifest schema](https://learn.microsoft.com/en-us/microsoftteams/platform/resources/schema/manifest-schema)
+- [Teams JavaScript SDK](https://learn.microsoft.com/en-us/microsoftteams/platform/tabs/how-to/using-teams-client-sdk)
+- [Teams Toolkit for Visual Studio](https://learn.microsoft.com/en-us/microsoftteams/platform/toolkit/toolkit-v4/install-teams-toolkit-vs)
+
+#### ASP.NET Core and Azure
+- [ASP.NET Core authentication](https://learn.microsoft.com/en-us/aspnet/core/security/authentication/)
+- [Deploy ASP.NET Core to Azure App Service](https://learn.microsoft.com/en-us/azure/app-service/quickstart-dotnetcore)
+- [Azure Key Vault configuration provider](https://learn.microsoft.com/en-us/aspnet/core/security/key-vault-configuration)
+
+<img src="https://pnptelemetry.azurewebsites.net/microsoft-teams-samples/samples/tab-auth-entra-account-csharp" />
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount.sln b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount.sln
new file mode 100644
index 0000000000..1310a78fc2
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount.sln
@@ -0,0 +1,38 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 17
+VisualStudioVersion = 17.6.33829.357
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "TabAuthEntraAccount", "TabAuthEntraAccount\TabAuthEntraAccount.csproj", "{DD8A1EAC-6947-423D-A135-8D6B22E7E857}"
+EndProject
+Project("{A9E3F50B-275E-4AF7-ADCE-8BE12D41E305}") = "M365Agent", "M365Agent\M365Agent.ttkproj", "{42A0237C-30E0-42AE-B6ED-50F318517E77}"
+EndProject
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Solution Items", "Solution Items", "{8EC462FD-D22E-90A8-E5CE-7E832BA40C5D}"
+	ProjectSection(SolutionItems) = preProject
+		TabAuthEntraAccount.slnLaunch.user = TabAuthEntraAccount.slnLaunch.user
+	EndProjectSection
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{DD8A1EAC-6947-423D-A135-8D6B22E7E857}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{DD8A1EAC-6947-423D-A135-8D6B22E7E857}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{DD8A1EAC-6947-423D-A135-8D6B22E7E857}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{DD8A1EAC-6947-423D-A135-8D6B22E7E857}.Release|Any CPU.Build.0 = Release|Any CPU
+		{42A0237C-30E0-42AE-B6ED-50F318517E77}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{42A0237C-30E0-42AE-B6ED-50F318517E77}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{42A0237C-30E0-42AE-B6ED-50F318517E77}.Debug|Any CPU.Deploy.0 = Debug|Any CPU
+		{42A0237C-30E0-42AE-B6ED-50F318517E77}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{42A0237C-30E0-42AE-B6ED-50F318517E77}.Release|Any CPU.Build.0 = Release|Any CPU
+		{42A0237C-30E0-42AE-B6ED-50F318517E77}.Release|Any CPU.Deploy.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {F99814E0-F3D5-4C00-8506-FE5FBA22BC84}
+	EndGlobalSection
+EndGlobal
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount.slnLaunch.user b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount.slnLaunch.user
new file mode 100644
index 0000000000..7eb329514f
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount.slnLaunch.user
@@ -0,0 +1,62 @@
+[
+  {
+    "Name": "Microsoft Teams (browser)",
+    "Projects": [
+      {
+        "Path": "TabAuthEntraAccount\\TabAuthEntraAccount.csproj",
+        "Action": "Start",
+        "DebugTarget": "Start Project"
+      },
+      {
+        "Path": "M365Agent\\M365Agent.ttkproj",
+        "Action": "StartWithoutDebugging",
+        "DebugTarget": "Microsoft Teams (browser)"
+      }
+    ]
+  },
+  {
+    "Name": "Outlook (browser)",
+    "Projects": [
+      {
+        "Path": "TabAuthEntraAccount\\TabAuthEntraAccount.csproj",
+        "Action": "Start",
+        "DebugTarget": "Start Project"
+      },
+      {
+        "Path": "M365Agent\\M365Agent.ttkproj",
+        "Action": "StartWithoutDebugging",
+        "DebugTarget": "Outlook (browser)"
+      }
+    ]
+  },
+  {
+    "Name": "Microsoft 365 app (browser)",
+    "Projects": [
+      {
+        "Path": "TabAuthEntraAccount\\TabAuthEntraAccount.csproj",
+        "Action": "Start",
+        "DebugTarget": "Start Project"
+      },
+      {
+        "Path": "M365Agent\\M365Agent.ttkproj",
+        "Action": "StartWithoutDebugging",
+        "DebugTarget": "Microsoft 365 app (browser)"
+      }
+    ]
+  },
+  {
+    "Name": "Microsoft Teams (browser) (skip update app)",
+    "Projects": [
+      {
+        "Path": "TabAuthEntraAccount\\TabAuthEntraAccount.csproj",
+        "Action": "Start",
+        "DebugTarget": "Start Project"
+      },
+      {
+        "Path": "M365Agent\\M365Agent.ttkproj",
+        "Action": "StartWithoutDebugging",
+        "DebugTarget": "Microsoft Teams (browser) (skip update app)"
+      }
+    ]
+  }
+]
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/.gitignore b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/.gitignore
new file mode 100644
index 0000000000..4596bae4d8
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/.gitignore
@@ -0,0 +1,25 @@
+# TeamsFx files
+build
+appPackage/build
+env/.env.*.user
+env/.env.local
+appsettings.Development.json
+.deployment
+
+# User-specific files
+*.user
+
+# Build results
+[Dd]ebug/
+[Dd]ebugPublic/
+[Rr]elease/
+[Rr]eleases/
+x64/
+x86/
+bld/
+[Bb]in/
+[Oo]bj/
+[Ll]og/
+
+# Notification local store
+.notification.localstore.json
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Controllers/AuthController.cs b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Controllers/AuthController.cs
new file mode 100644
index 0000000000..bb0e53d45a
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Controllers/AuthController.cs
@@ -0,0 +1,58 @@
+// <copyright file="AuthController.cs" company="Microsoft">
+// Copyright (c) Microsoft. All Rights Reserved.
+// </copyright>
+
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Configuration;
+
+namespace TabAuthEntraAccount.Controllers
+{
+    /// <summary>
+    /// AuthController manages the authentication flow for Microsoft Entra ID (formerly Azure AD).
+    /// This controller provides the authentication start and end pages that handle the OAuth 2.0
+    /// authorization code flow within the Microsoft Teams tab application context.
+    /// </summary>
+    public class AuthController : Controller
+    {
+        // Configuration service for accessing Azure AD settings from appsettings.json
+        private readonly IConfiguration _configuration;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="AuthController"/> class.
+        /// Sets up dependency injection for configuration access.
+        /// </summary>
+        /// <param name="configuration">IConfiguration instance for accessing app settings</param>
+        public AuthController(
+            IConfiguration configuration)
+        {
+            _configuration = configuration;
+        }
+
+        /// <summary>
+        /// Displays the authentication start page for Microsoft Entra ID OAuth 2.0 flow.
+        /// This page initiates the authentication process by redirecting users to the Microsoft login page.
+        /// The Azure AD Client ID is passed to the view to configure the JavaScript authentication flow.
+        /// </summary>
+        /// <returns>AuthStart view with Azure AD Client ID configured for authentication</returns>
+        public IActionResult AuthStart()
+        {
+            // Provide the Azure AD Client ID to the view for JavaScript authentication initialization
+            ViewBag.AzureClientId = _configuration["AzureAd:ClientId"];
+            return View();
+        }
+
+        /// <summary>
+        /// Displays the authentication completion page for Microsoft Entra ID OAuth 2.0 flow.
+        /// This page is shown after the user completes authentication with Microsoft and 
+        /// the authorization code is returned. It handles the code exchange using PKCE
+        /// and user profile retrieval process client-side.
+        /// </summary>
+        /// <returns>AuthEnd view with Azure AD Client ID configured for PKCE token exchange</returns>
+        public IActionResult AuthEnd()
+        {
+            // Provide the Azure AD Client ID to the view for JavaScript PKCE token exchange
+            ViewBag.AzureClientId = _configuration["AzureAd:ClientId"];
+            return View();
+        }
+    }
+}
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Controllers/HomeController.cs b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Controllers/HomeController.cs
new file mode 100644
index 0000000000..734c7f1380
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Controllers/HomeController.cs
@@ -0,0 +1,58 @@
+// <copyright file="HomeController.cs" company="Microsoft">
+// Copyright (c) Microsoft. All Rights Reserved.
+// </copyright>
+
+namespace TabAuthEntraAccount.Controllers
+{
+    using Microsoft.AspNetCore.Mvc;
+    using Microsoft.Extensions.Configuration;
+    using Models;
+    using System.Diagnostics;
+
+    /// <summary>
+    /// HomeController handles the main application functionality for the Microsoft Teams tab application.
+    /// With the PKCE (Proof Key for Code Exchange) flow implementation, this controller now only serves
+    /// the initial UI and configuration, while all authentication and Microsoft Graph API calls
+    /// are handled client-side in JavaScript.
+    /// </summary>
+    public class HomeController : Controller
+    {
+        // Configuration service for accessing appsettings.json values
+        private readonly IConfiguration _configuration;
+
+        /// <summary>
+        /// Initializes a new instance of the <see cref="HomeController"/> class.
+        /// </summary>
+        /// <param name="configuration">IConfiguration instance.</param>
+        public HomeController(IConfiguration configuration)
+        {
+            _configuration = configuration;
+        }
+
+        /// <summary>
+        /// Main entry point for the Teams tab application.
+        /// Sets up the Azure AD Client ID for use in the JavaScript authentication flow.
+        /// </summary>
+        /// <returns>The Index view with Azure AD Client ID configured in ViewBag</returns>
+        public IActionResult Index()
+        {
+            // Pass the Azure AD Client ID to the view for JavaScript authentication
+            ViewBag.AzureClientId = _configuration["AzureAd:ClientId"];
+            return View();
+        }
+
+        /// <summary>
+        /// Handles application errors and displays the error page.
+        /// This action is called when an unhandled exception occurs in the application.
+        /// It provides debugging information in development environments.
+        /// </summary>
+        /// <returns>Error view with diagnostic information</returns>
+        // Disable response caching for error pages to ensure fresh error information
+        [ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
+        public IActionResult Error()
+        {
+            // Create error view model with current request/activity ID for correlation
+            return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
+        }
+    }
+}
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Models/ErrorViewModel.cs b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Models/ErrorViewModel.cs
new file mode 100644
index 0000000000..17bb109298
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Models/ErrorViewModel.cs
@@ -0,0 +1,22 @@
+// <copyright file="ErrorViewModel.cs" company="Microsoft">
+// Copyright (c) Microsoft. All Rights Reserved.
+// </copyright>
+
+namespace TabAuthEntraAccount.Models
+{
+    /// <summary>
+    /// Error view model class.
+    /// </summary>
+    public class ErrorViewModel
+    {
+        /// <summary>
+        /// Request id for the api request
+        /// </summary>
+        public string RequestId { get; set; }
+
+        /// <summary>
+        /// Returns true or false if request id is empty
+        /// </summary>
+        public bool ShowRequestId => !string.IsNullOrEmpty(RequestId);
+    }
+}
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Program.cs b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Program.cs
new file mode 100644
index 0000000000..c91cde2437
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Program.cs
@@ -0,0 +1,24 @@
+// <copyright file="Program.cs" company="Microsoft">
+// Copyright (c) Microsoft. All Rights Reserved.
+// </copyright>
+
+namespace TabAuthEntraAccount
+{
+    using Microsoft.AspNetCore.Hosting;
+    using Microsoft.Extensions.Hosting;
+
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            CreateHostBuilder(args).Build().Run();
+        }
+
+        public static IHostBuilder CreateHostBuilder(string[] args) =>
+            Host.CreateDefaultBuilder(args)
+                .ConfigureWebHostDefaults(webBuilder =>
+                {
+                    webBuilder.UseStartup<Startup>();
+                });
+    }
+}
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Properties/launchSettings.json b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Properties/launchSettings.json
new file mode 100644
index 0000000000..3e52646e09
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Properties/launchSettings.json
@@ -0,0 +1,16 @@
+{
+  "profiles": {
+    // Debug project within Teams
+    "Microsoft Teams (browser)": {
+      "commandName": "Project",
+      "dotnetRunMessages": true,
+      "launchBrowser": true,
+      "launchUrl": "https://teams.microsoft.com/l/app/%TEAMSAPPID%?installAppPackage=true&webjoin=true&appTenantId=%TENANTID%&login_hint=%USERNAME%",
+      "applicationUrl": "https://localhost:44302;http://localhost:2544",
+      "environmentVariables": {
+        "ASPNETCORE_ENVIRONMENT": "Development"
+      },
+      "hotReloadProfile": "aspnetcore"
+    }
+  }
+}
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Startup.cs b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Startup.cs
new file mode 100644
index 0000000000..fc59bdacaa
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Startup.cs
@@ -0,0 +1,56 @@
+// <copyright file="Startup.cs" company="Microsoft">
+// Copyright (c) Microsoft. All Rights Reserved.
+// </copyright>
+
+namespace TabAuthEntraAccount
+{
+    using Microsoft.AspNetCore.Builder;
+    using Microsoft.AspNetCore.Hosting;
+    using Microsoft.Extensions.Configuration;
+    using Microsoft.Extensions.DependencyInjection;
+    using Microsoft.Extensions.Hosting;
+
+    public class Startup
+    {
+        public Startup(IConfiguration configuration)
+        {
+            Configuration = configuration;
+        }
+
+        public IConfiguration Configuration { get; }
+
+        // This method gets called by the runtime. Use this method to add services to the container.
+        public void ConfigureServices(IServiceCollection services)
+        {
+            services.AddControllersWithViews();
+        }
+
+        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
+        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
+        {
+            if (env.IsDevelopment())
+            {
+                app.UseDeveloperExceptionPage();
+            }
+            else
+            {
+                app.UseExceptionHandler("/Home/Error");
+
+                // The default HSTS value is 30 days. You may want to change this for production scenarios, see https://aka.ms/aspnetcore-hsts.
+                app.UseHsts();
+            }
+
+            app.UseHttpsRedirection();
+            app.UseStaticFiles();
+
+            app.UseRouting();
+
+            app.UseEndpoints(endpoints =>
+            {
+                endpoints.MapControllerRoute(
+                    name: "default",
+                    pattern: "{controller=Home}/{action=Index}/{id?}");
+            });
+        }
+    }
+}
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/TabAuthEntraAccount.csproj b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/TabAuthEntraAccount.csproj
new file mode 100644
index 0000000000..378cbf427c
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/TabAuthEntraAccount.csproj
@@ -0,0 +1,22 @@
+<Project Sdk="Microsoft.NET.Sdk.Web">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <Compile Remove="Manifest\**" />
+    <Content Remove="Manifest\**" />
+    <EmbeddedResource Remove="Manifest\**" />
+    <None Remove="Manifest\**" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Web.LibraryManager.Build" Version="2.1.175" />
+  </ItemGroup>
+
+	<PropertyGroup>
+		<LibraryRestore>false</LibraryRestore>
+	</PropertyGroup>
+
+</Project>
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Auth/AuthEnd.cshtml b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Auth/AuthEnd.cshtml
new file mode 100644
index 0000000000..64c3a9baad
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Auth/AuthEnd.cshtml
@@ -0,0 +1,114 @@
+@{
+ViewBag.Title = "title";
+Layout = "_Layout";
+}
+
+<script src="https://res.cdn.office.net/teams-js/2.34.0/js/MicrosoftTeams.min.js"
+        integrity="sha384-brW9AazbKR2dYw2DucGgWCCcmrm2oBFV4HQidyuyZRI/TnAkmOOnTARSTdps3Hwt"
+        crossorigin="anonymous"></script>
+<script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
+<script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
+<script type="text/javascript">
+        $(document).ready(function () {
+                getAuthToken();
+        });
+
+        // Exchange authorization code for access token using PKCE
+        async function getAuthToken() {
+            const params = new URLSearchParams(window.location.search);
+            const authorizationCode = params.get('code');
+            const { authId, method, hostRedirectUrl } = JSON.parse(params.get('state'));
+            const baseUrl = hostRedirectUrl.split('authId')[0];
+
+            if (!authorizationCode) {
+                const error = params.get('error') || 'OAuth failed - no authorization code received';
+                handleAuthError(error, method, baseUrl, authId);
+                return;
+            }
+
+            try {
+                // Get the code verifier from sessionStorage
+                const codeVerifier = sessionStorage.getItem('codeVerifier');
+                if (!codeVerifier) {
+                    throw new Error('Code verifier not found in session storage');
+                }
+
+                // Exchange authorization code for access token
+                const tokenResponse = await fetch('https://login.microsoftonline.com/common/oauth2/v2.0/token', {
+                    method: 'POST',
+                    headers: {
+                        'Content-Type': 'application/x-www-form-urlencoded',
+                    },
+                    body: new URLSearchParams({
+                        client_id: '@ViewBag.AzureClientId',
+                        code: authorizationCode,
+                        redirect_uri: window.location.origin + '/Auth/AuthEnd',
+                        grant_type: 'authorization_code',
+                        code_verifier: codeVerifier,
+                        scope: 'https://graph.microsoft.com/User.Read'
+                    })
+                });
+
+                if (!tokenResponse.ok) {
+                    const errorData = await tokenResponse.text();
+                    throw new Error(`Token exchange failed: ${errorData}`);
+                }
+
+                const tokenData = await tokenResponse.json();
+                const accessToken = tokenData.access_token;
+
+                // Fetch user profile from Microsoft Graph
+                const graphResponse = await fetch('https://graph.microsoft.com/v1.0/me', {
+                    headers: {
+                        'Authorization': `Bearer ${accessToken}`,
+                        'Content-Type': 'application/json'
+                    }
+                });
+
+                if (!graphResponse.ok) {
+                    throw new Error(`Graph API call failed: ${graphResponse.status}`);
+                }
+
+                const userProfile = await graphResponse.json();
+
+                // Clean up stored code verifier
+                sessionStorage.removeItem('codeVerifier');
+
+                // Format the result for the calling application
+                const result = JSON.stringify({
+                    id: userProfile.id,
+                    displayName: userProfile.displayName,
+                    givenName: userProfile.givenName,
+                    surname: userProfile.surname,
+                    userPrincipalName: userProfile.userPrincipalName,
+                    name: userProfile.displayName,
+                    email: userProfile.mail || userProfile.userPrincipalName,
+                    accessToken: accessToken // Include access token for future API calls if needed
+                });
+
+                // Return the result to the calling application
+                if (method === 'deeplink') {
+                    window.location.href = `${baseUrl}authId=${authId}&result=${encodeURIComponent(result)}`;
+                } else {
+                    microsoftTeams.app.initialize().then(() => {
+                        microsoftTeams.authentication.notifySuccess(result);
+                    });
+                }
+
+            } catch (error) {
+                console.error('Authentication error:', error);
+                sessionStorage.removeItem('codeVerifier'); // Clean up on error
+                handleAuthError(error.message, method, baseUrl, authId);
+            }
+        }
+
+        function handleAuthError(errorMessage, method, baseUrl, authId) {
+            if (method === 'deeplink') {
+                window.location.href = `${baseUrl}authId=${authId}&error=${encodeURIComponent(errorMessage)}`;
+            } else {
+                microsoftTeams.app.initialize().then(() => {
+                    microsoftTeams.authentication.notifyFailure(errorMessage);
+                });
+            }
+        }
+</script>
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Auth/AuthStart.cshtml b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Auth/AuthStart.cshtml
new file mode 100644
index 0000000000..2bd4712d19
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Auth/AuthStart.cshtml
@@ -0,0 +1,74 @@
+@{
+    ViewBag.Title = "title";
+    Layout = "_Layout";
+}
+
+<script src="https://res.cdn.office.net/teams-js/2.34.0/js/MicrosoftTeams.min.js"
+        integrity="sha384-brW9AazbKR2dYw2DucGgWCCcmrm2oBFV4HQidyuyZRI/TnAkmOOnTARSTdps3Hwt"
+        crossorigin="anonymous"></script>
+    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
+    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
+    <script type="text/javascript">
+        $(document).ready(function () {
+                getAuthToken();
+        });
+    
+    // PKCE helper functions
+    function generateCodeVerifier() {
+        const array = new Uint8Array(32);
+        crypto.getRandomValues(array);
+        return btoa(String.fromCharCode.apply(null, array))
+            .replace(/\+/g, '-')
+            .replace(/\//g, '_')
+            .replace(/=/g, '');
+    }
+
+    async function generateCodeChallenge(codeVerifier) {
+        const encoder = new TextEncoder();
+        const data = encoder.encode(codeVerifier);
+        const digest = await crypto.subtle.digest('SHA-256', data);
+        return btoa(String.fromCharCode.apply(null, new Uint8Array(digest)))
+            .replace(/\+/g, '-')
+            .replace(/\//g, '_')
+            .replace(/=/g, '');
+    }
+    
+    // Get client side token with PKCE.
+    async function getAuthToken() {
+        const params = new URLSearchParams(window.location.search);
+        const authId = params.get('authId');
+        const method = params.get('oauthRedirectMethod');
+        
+        var redirectUrl = window.location.origin + "/Auth/AuthEnd";
+        const hostRedirectUrl = params.get('hostRedirectUrl');
+
+        // Generate PKCE parameters
+        const codeVerifier = generateCodeVerifier();
+        const codeChallenge = await generateCodeChallenge(codeVerifier);
+
+        // Store code verifier in sessionStorage for use in AuthEnd
+        sessionStorage.setItem('codeVerifier', codeVerifier);
+
+        const state = JSON.stringify({
+            authId: authId,
+            method: method,
+            hostRedirectUrl: hostRedirectUrl
+        });
+
+        const queryObj = {
+            state: encodeURIComponent(state),
+            client_id: '@ViewBag.AzureClientId',
+            response_type: 'code',
+            scope: 'https://graph.microsoft.com/User.Read offline_access',
+            prompt: 'select_account',
+            code_challenge: codeChallenge,
+            code_challenge_method: 'S256'
+        };
+
+        const query = Object.entries(queryObj)
+            .map(([k, v]) => `${k}=${v}`)
+            .join('&');
+
+        window.location.href = `https://login.microsoftonline.com/common/oauth2/v2.0/authorize?redirect_uri=${redirectUrl}&${query}`;
+    }
+</script>
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Home/Index.cshtml b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Home/Index.cshtml
new file mode 100644
index 0000000000..05a13cf323
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Home/Index.cshtml
@@ -0,0 +1,422 @@
+@{
+    ViewData["Title"] = "Home Page";
+    Layout = "_Layout";
+}
+
+<head>
+    <script src="https://res.cdn.office.net/teams-js/2.34.0/js/MicrosoftTeams.min.js"
+            integrity="sha384-brW9AazbKR2dYw2DucGgWCCcmrm2oBFV4HQidyuyZRI/TnAkmOOnTARSTdps3Hwt"
+            crossorigin="anonymous"></script>
+    <style>
+        body {
+            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
+            background-color: #f3f2f1;
+            margin: 0;
+            padding: 20px;
+        }
+
+        h3 {
+            text-align: center;
+            margin-top: 0.5rem;
+            color: #323130;
+        }
+
+        .welcome-header {
+            background: linear-gradient(135deg, #0078d4 0%, #106ebe 100%);
+            color: white;
+            padding: 20px;
+            border-radius: 8px 8px 0 0;
+            text-align: center;
+            margin-bottom: 0;
+        }
+
+        .welcome-header h2 {
+            margin: 0;
+            font-size: 1.8rem;
+        }
+
+        .welcome-header p {
+            margin: 5px 0 0 0;
+            opacity: 0.9;
+            font-size: 1rem;
+        }
+
+        .card {
+            box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.1);
+            background: white;
+            border-radius: 8px;
+            overflow: hidden;
+            margin: 20px auto;
+            max-width: 1000px;
+        }
+
+        .card:hover {
+            box-shadow: 0 8px 16px 0 rgba(0, 0, 0, 0.15);
+        }
+
+        .user-info-section {
+            padding: 20px;
+            background: #faf9f8;
+            border-bottom: 1px solid #edebe9;
+        }
+
+        .user-info-grid {
+            display: grid;
+            grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
+            gap: 20px;
+            margin-top: 20px;
+        }
+
+        .info-group {
+            background: white;
+            padding: 15px;
+            border-radius: 6px;
+            border-left: 4px solid #0078d4;
+            box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
+        }
+
+        .info-group h4 {
+            margin: 0 0 15px 0;
+            color: #323130;
+            font-size: 1.1rem;
+            font-weight: 600;
+        }
+
+        .info-row {
+            display: flex;
+            justify-content: space-between;
+            margin: 8px 0;
+            align-items: flex-start;
+        }
+
+        .info-label {
+            font-weight: 600;
+            color: #605e5c;
+            min-width: 120px;
+            font-size: 0.9rem;
+        }
+
+        .info-value {
+            color: #323130;
+            word-break: break-word;
+            flex: 1;
+            text-align: right;
+            font-size: 0.9rem;
+        }
+
+        .btn-container {
+            display: flex;
+            align-items: center;
+            gap: 20px;
+            padding: 20px;
+            background: transparent;
+            margin: 0;
+            position: absolute;
+            top: -5px;
+            left: -13%;
+        }
+
+        .btn-primary, .btn-secondary {
+            padding: 12px 24px;
+            border: none;
+            border-radius: 4px;
+            font-size: 1rem;
+            font-weight: 600;
+            cursor: pointer;
+            margin: 0;
+            transition: background-color 0.2s ease;
+        }
+
+        .btn-primary {
+            background-color: #0078d4;
+            color: white;
+        }
+
+        .btn-primary:hover {
+            background-color: #106ebe;
+        }
+
+        .btn-secondary {
+            background-color: #edebe9;
+            color: #323130;
+            border: 1px solid #d2d0ce;
+        }
+
+        .btn-secondary:hover {
+            background-color: #e1dfdd;
+        }
+
+        .signin-header {
+            text-align: center;
+            margin: 20px 0;
+            font-size: 1.5rem;
+            color: #323130;
+        }
+
+        .card-container-div {
+            max-width: 1000px;
+            margin: 0 auto;
+            padding: 20px;
+            position: relative;
+        }
+
+        #divError {
+            background-color: #fde7e9;
+            color: #a4262c;
+            padding: 12px;
+            border-radius: 4px;
+            margin: 15px 0 0 0;
+            border-left: 4px solid #d13438;
+            display: none;
+            font-size: 0.9rem;
+            text-align: center;
+        }
+
+        .loading {
+            display: inline-flex;
+            align-items: center;
+            background: transparent;
+            border: none;
+            box-shadow: none;
+            padding: 0;
+        }
+
+        .loading-button {
+            padding: 12px 24px;
+            border: 1px solid #d2d0ce;
+            border-radius: 4px;
+            background-color: #f3f2f1;
+            color: #323130;
+            font-size: 1rem;
+            cursor: pointer;
+            transition: background-color 0.2s ease;
+            margin: 0;
+        }
+
+        .loading-button:hover {
+            background-color: #e1dfdd;
+        }
+
+        .hidden {
+            display: none;
+        }
+
+        .empty-value {
+            color: #a19f9d;
+            font-style: italic;
+        }
+
+        .signin-card {
+            background: transparent;
+            border: none;
+            box-shadow: none;
+            border-radius: 0;
+            margin: 20px auto;
+            max-width: 1000px;
+        }
+
+        .signin-card:hover {
+            box-shadow: none;
+        }
+
+      
+    </style>
+        
+    <script>
+        // Fetch id token
+        function AuthIdToken() {
+            return new Promise((resolve, reject) => {
+                microsoftTeams.app.initialize().then(() => {
+                    microsoftTeams.authentication.authenticate({
+                        url: `${window.location.origin}/Auth/AuthStart?oauthRedirectMethod={oauthRedirectMethod}&authId={authId}&hostRedirectUrl={hostRedirectUrl}`,
+                        isExternal: true
+                    }).then((result) => {
+                        resolve(result);
+                    }).catch((reason) => {
+                        reject(reason);
+                    })
+                })
+            })
+        }
+
+        // Main authentication function
+        function AuthLogin() {
+            showLoading(true);
+            hideError();
+            
+            AuthIdToken()
+                .then((result) => {
+                    // Parse the authentication result directly from PKCE flow
+                    try {
+                        const profile = JSON.parse(result);
+                        populateAllProfileData(profile);
+                        showProfileCard();
+                        showLoading(false);
+                    } catch (e) {
+                        console.error("Error parsing profile data:", e);
+                        showError("Error parsing profile data: " + e.message);
+                        showLoading(false);
+                    }
+                })
+                .catch((error) => {
+                    showError("Authentication failed: " + error);
+                    showLoading(false);
+                });
+        }
+
+        // Populate ONLY personal information in the UI
+        function populateAllProfileData(profile) {
+            
+            // Helper function to safely set text content
+            function setTextContent(elementId, value, emptyText = "Not specified") {
+                const element = document.getElementById(elementId);
+                if (element) {
+                    const displayValue = value && value.trim() !== "" ? value : emptyText;
+                    element.textContent = displayValue;
+                    if (displayValue === emptyText) {
+                        element.classList.add('empty-value');
+                    } else {
+                        element.classList.remove('empty-value');
+                    }
+                }
+            }
+
+            // Main header information
+            $("#welcomeMessage").text(`Welcome, ${profile.displayName || profile.name || "User"}!`);
+            setTextContent("mainDisplayName", profile.displayName || profile.name);
+            setTextContent("mainEmail", profile.email || "Not specified");
+            setTextContent("mainJobTitle", "Microsoft Entra ID User");
+
+            // Personal Information ONLY
+            setTextContent("displayName", profile.displayName);
+            setTextContent("givenName", profile.givenName);
+            setTextContent("surname", profile.surname);
+            setTextContent("userId", profile.id);
+            setTextContent("userPrincipalName", profile.userPrincipalName);
+        }
+
+        // Utility functions
+        function showProfileCard() {
+            document.getElementById("signInCard").classList.add("hidden");
+            document.getElementById("profileCard").classList.remove("hidden");
+        }
+
+        function showSignInCard() {
+            document.getElementById("profileCard").classList.add("hidden");
+            document.getElementById("signInCard").classList.remove("hidden");
+        }
+
+        function showLoading(show) {
+            const loadingElement = document.getElementById("loadingIndicator");
+            if (loadingElement) {
+                if (show) {
+                    loadingElement.classList.remove("hidden");
+                } else {
+                    loadingElement.classList.add("hidden");
+                }
+            }
+        }
+
+        function showError(message) {
+            const errorElement = document.getElementById("divError");
+            if (errorElement) {
+                errorElement.textContent = message;
+                errorElement.style.display = "block";
+            }
+        }
+
+        function hideError() {
+            const errorElement = document.getElementById("divError");
+            if (errorElement) {
+                errorElement.style.display = "none";
+            }
+        }
+
+        function refreshProfile() {
+            showSignInCard();
+            hideError();
+        }
+
+        function cancelLoading() {
+            showLoading(false);
+            showSignInCard();
+            hideError();
+        }
+    </script>
+</head>
+
+<body class="theme-light">
+    <div class="surface">
+        <div class="card-container-div">
+            <!-- Sign-in card (shown initially) -->
+            <div class="signin-card" id="signInCard">
+                <div class="btn-container">
+                    <button type="button" class="btn-primary" onclick="AuthLogin()" id="authlogin">
+                        Login
+                    </button>
+                    <!-- Loading indicator -->
+                    <div class="loading hidden" id="loadingIndicator">
+                        <button type="button" class="loading-button" onclick="cancelLoading()">Loading user profile data...</button>
+                    </div>
+                </div>
+                
+                <!-- Error display - positioned within sign-in card for better context -->
+                <div id="divError"></div>
+            </div>
+
+            <!-- Profile data card (shown after successful authentication) -->
+            <div class="card hidden" id="profileCard">
+                <div class="welcome-header">
+                    <h2 id="welcomeMessage">Welcome!</h2>
+                    <p id="userRole">Microsoft Entra ID User</p>
+                </div>
+
+                <div class="user-info-section">
+                    <div style="display: flex; align-items: center; gap: 20px; margin-bottom: 20px;">
+                        <div>
+                            <h2 style="margin: 0; color: #323130;" id="mainDisplayName">Loading...</h2>
+                            <p style="margin: 5px 0; color: #605e5c;" id="mainEmail">Loading...</p>
+                            <p style="margin: 5px 0; color: #605e5c;" id="mainJobTitle">Loading...</p>
+                        </div>
+                    </div>
+
+                    <div class="user-info-grid">
+                        <!-- Personal Information -->
+                        <div class="info-group">
+                            <h4>Personal Information</h4>
+                            <div class="info-row">
+                                <span class="info-label">Display Name:</span>
+                                <span class="info-value" id="displayName">-</span>
+                            </div>
+                            <div class="info-row">
+                                <span class="info-label">Given Name:</span>
+                                <span class="info-value" id="givenName">-</span>
+                            </div>
+                            <div class="info-row">
+                                <span class="info-label">Surname:</span>
+                                <span class="info-value" id="surname">-</span>
+                            </div>
+                            <div class="info-row">
+                                <span class="info-label">User ID:</span>
+                                <span class="info-value" id="userId">-</span>
+                            </div>
+                            <div class="info-row">
+                                <span class="info-label">Principal Name:</span>
+                                <span class="info-value" id="userPrincipalName">-</span>
+                            </div>
+                            
+                            <!-- Additional Refresh Profile button at the bottom of Personal Information -->
+                            <div style="margin-top: 20px; text-align: center;">
+                                <button type="button" class="btn-primary" onclick="refreshProfile()" style="padding: 8px 16px; font-size: 0.9rem;">
+                                    Refresh Profile
+                                </button>
+                            </div>
+                        </div>
+
+
+                    </div>
+                </div>
+            </div>
+        </div>
+    </div>
+</body>
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Shared/Error.cshtml b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Shared/Error.cshtml
new file mode 100644
index 0000000000..e5ab6cd67b
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Shared/Error.cshtml
@@ -0,0 +1,19 @@
+@model ErrorViewModel
+@{
+    ViewData["Title"] = "Error";
+}
+
+<h1 class="text-danger">Error.</h1>
+<h2 class="text-danger">An error occurred while processing your request.</h2>
+
+@if (Model.ShowRequestId)
+{
+    <p>
+        <strong>Request ID:</strong> <code>@Model.RequestId</code>
+    </p>
+}
+
+<p>
+    <strong>An error occurred while processing your request.</strong>
+  Please use local debugging or restart the app.
+</p>
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Shared/_Layout.cshtml b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Shared/_Layout.cshtml
new file mode 100644
index 0000000000..af9b85fb5b
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/Shared/_Layout.cshtml
@@ -0,0 +1,28 @@
+<!DOCTYPE html>
+<html lang="en">
+<head>
+    <meta charset="utf-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>@ViewData["Title"] - TabAuthEntraAccount</title>
+    <link rel="stylesheet" href="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/css/bootstrap.min.css">
+    <link rel="stylesheet" href="https://cdnjs.cloudflare.com/ajax/libs/font-awesome/4.7.0/css/font-awesome.min.css">
+    <script src="https://res.cdn.office.net/teams-js/2.34.0/js/MicrosoftTeams.min.js"
+            integrity="sha384-brW9AazbKR2dYw2DucGgWCCcmrm2oBFV4HQidyuyZRI/TnAkmOOnTARSTdps3Hwt"
+            crossorigin="anonymous"></script>
+    <script src="https://ajax.googleapis.com/ajax/libs/jquery/3.5.1/jquery.min.js"></script>
+    <script src="https://maxcdn.bootstrapcdn.com/bootstrap/4.5.2/js/bootstrap.min.js"></script>
+    <style>
+         body {
+             font-family:"Segoe UI","Apple Color Emoji","Segoe UI Emoji","Segoe UI Web";
+         }
+    </style>
+    @RenderSection("Scripts", required: false)
+</head>
+<body>
+    <div class="container">
+        <main role="main" class="pb-3">
+            @RenderBody()
+        </main>
+    </div>
+</body>
+</html>
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/_ViewImports.cshtml b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/_ViewImports.cshtml
new file mode 100644
index 0000000000..42e3d97fb3
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/_ViewImports.cshtml
@@ -0,0 +1,3 @@
+@using TabAuthEntraAccount
+@using TabAuthEntraAccount.Models
+@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/_ViewStart.cshtml b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/_ViewStart.cshtml
new file mode 100644
index 0000000000..a5f10045db
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/Views/_ViewStart.cshtml
@@ -0,0 +1,3 @@
+@{
+    Layout = "_Layout";
+}
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/appsettings.Development.json b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/appsettings.Development.json
new file mode 100644
index 0000000000..8983e0fc1c
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/appsettings.Development.json
@@ -0,0 +1,9 @@
+{
+  "Logging": {
+    "LogLevel": {
+      "Default": "Information",
+      "Microsoft": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information"
+    }
+  }
+}
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/appsettings.json b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/appsettings.json
new file mode 100644
index 0000000000..f6ff9a55cb
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/appsettings.json
@@ -0,0 +1,14 @@
+{
+	"AzureAd": {
+		"ClientId": "",
+		"RedirectUri": ""
+	},
+	"Logging": {
+		"LogLevel": {
+			"Default": "Information",
+			"Microsoft": "Warning",
+			"Microsoft.Hosting.Lifetime": "Information"
+		}
+	},
+	"AllowedHosts": "*"
+}
\ No newline at end of file
diff --git a/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/wwwroot/favicon.ico b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/wwwroot/favicon.ico
new file mode 100644
index 0000000000..a3a799985c
Binary files /dev/null and b/samples/tab-auth-entra-account/csharp/TabAuthEntraAccount/wwwroot/favicon.ico differ
diff --git a/samples/tab-auth-entra-account/csharp/assets/sample.json b/samples/tab-auth-entra-account/csharp/assets/sample.json
new file mode 100644
index 0000000000..27ce47a889
--- /dev/null
+++ b/samples/tab-auth-entra-account/csharp/assets/sample.json
@@ -0,0 +1,68 @@
+[
+  {
+    "name": "officedev-microsoft-teams-samples-tab-auth-entra-account-csharp",
+    "source": "officeDev",
+    "title": "Tab Auth with Different Entra ID Accounts",
+    "shortDescription": "Microsoft Teams sample app demonstrating authentication and account switching using different Microsoft Entra ID accounts.",
+    "url": "https://github.com/OfficeDev/Microsoft-Teams-Samples/tree/main/samples/tab-auth-entra-account/csharp",
+    "longDescription": [
+      "This sample app demonstrates how to integrate Microsoft Entra ID (Azure AD) authentication into a Microsoft Teams tab. It allows users to sign in using their Entra account and supports switching between different Entra accounts for secure, flexible access."
+    ],
+    "creationDateTime": "2025-07-25",
+    "updateDateTime": "2025-08-05",
+    "products": [
+      "Teams"
+    ],
+    "metadata": [
+      {
+        "key": "TEAMS-SAMPLE-SOURCE",
+        "value": "OfficeDev"
+      },
+      {
+        "key": "TEAMS-SERVER-LANGUAGE",
+        "value": "csharp"
+      },
+      {
+        "key": "TEAMS-SERVER-PLATFORM",
+        "value": "netframework"
+      },
+      {
+        "key": "TEAMS-FEATURES",
+        "value": "tab"
+      }
+    ],
+    "thumbnails": [
+      {
+        "type": "image",
+        "order": 100,
+        "url": "https://raw.githubusercontent.com/OfficeDev/Microsoft-Teams-Samples/main/samples/tab-auth-entra-account/csharp/Images/tab-auth-entra-account.gif",
+        "alt": "Solution UX demonstrating authentication and account switching using different Microsoft Entra ID accounts"
+      }
+    ],
+    "authors": [
+      {
+        "gitHubAccount": "OfficeDev",
+        "pictureUrl": "https://avatars.githubusercontent.com/u/6789362?s=200&v=4",
+        "name": "OfficeDev"
+      }
+    ],
+    "references": [
+      {
+        "name": "Teams developer documentation",
+        "url": "https://aka.ms/TeamsPlatformDocs"
+      },
+      {
+        "name": "Teams developer questions",
+        "url": "https://aka.ms/TeamsPlatformFeedback"
+      },
+      {
+        "name": "Teams development videos from Microsoft",
+        "url": "https://aka.ms/sample-ref-teams-vids-from-microsoft"
+      },
+      {
+        "name": "Teams development videos from the community",
+        "url": "https://aka.ms/sample-ref-teams-vids-from-community"
+      }
+    ]
+  }
+]
\ No newline at end of file