Disclaimer: Currently I am employed by Microsoft, but my views and thoughts are still my own. The reason I joined Microsoft was, the work Microsoft have been doing for last couple of years in Open Source Space. Today I am a advocate for Open Source representing Microsoft.
In 2014, Microsoft announced that, .NET will be both Open Source and Cross Platform. Back then it was one of the most surprising moves from Microsoft. Making one of its core platforms open source was unheard from Microsoft, and not just open source, but also cross platform. Until then Microsoft has reputation of being Windows only and being against open source.
Visual Studio Code
There are rumors in the community that VSCode is now a de facto IDE in Google.