As per https://learn.microsoft.com/en-us/visualstudio/msbuild/what-s-new-in-msbuild-15-0
MSBuild is now installed in a folder under each version of Visual Studio. For example,
C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\MSBuild. You can also use the following PowerShell module to locate MSBuild: vssetup.powershell.MSBuild is no longer installed in the Global Assembly Cache. To reference MSBuild programmatically, use NuGet packages.