Google announced beta support for ASP.NET Core on App Engine. Developers can build web applications with c# and .NET core. In a short, Google App Engine, or GAE, is Google's cloud computing platform for developing and hosting Web apps via Google.
The Google Cloud .NET client libraries are currently available on NuGet. Install Cloud Tools for Visual Studio extension to support developing applications for .NET core on GCP.
For more details you can read the original blog post on a google blog.