.NET was built in the time of early Java, and so has many similar characteristics: virtual machine with a garbage collector, executes compiled processor- and OS-independent binaries, supports multiple languages, and a large class library. A lot of these early bets were good. .NET has been used in almost all the relevant computing devices today, to greater or lesser degrees of success (not all from Microsoft).
More recently, .NET has been focused on cloud native space and high-performance web applications. It has been open source and cross platform for about 5 years now.