Today it has been officially anounced: Microsoft has launched its development suite "Visual Studio" for MacOS.
With this release, it will be posible to develope and therefore also run .net applications writen in C# on macOS which will also be cross-compilable and executable on a windows environment.
I can't though imagine Apple releasing xcode - and its underlying technologies - on windows.
It is clear, who' de BOSS?
Link to news source: http://venturebeat.com/2016/11/16/microsoft-announces-visual-studio-for-mac-preview-of-the-next-sql-server-with-linux-and-docker-support/