To install Teams on Windows 10 LTSC, you'll need first to allow the trusted apps to be executed \\

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- Install the WebView2 Runtime or (or Edge which contains WebView2)\\
Allow MSIX sideloading:
<cli> reg add HKLM\SOFTWARE\Policies\Microsoft\Windows\Appx /v AllowAllTrustedApps /t REG_DWORD /d 1 /f</cli>
Download the MSIX package from Microsoft: \\
https://go.microsoft.com/fwlink/?linkid=2196106 \\
Run the following command to deploy the package: 
<cli>Add-AppProvisionedPackage -online -packagepath "C:\temp\MSTeams-x64.msix" -skiplicense</cli>