- Microsoft has always been the largest developer advocate of any of the major tech players (Google has been a great contender for this position since 2010).
- Microsoft has moved most of their open source projects to Github.
- Microsoft is a major contributor to Git, including massive infrastructure projects to make it possible to host the NT kernel on Git.
- Microsoft has tried to do open source git hosting in the past (Codeplex?) but it never succeeded. Also: Microsoft partnered with Github when they shut down to migrate Codeplex projects to Github.
- Github has the Atom team, which would have some great synergies to combine with the VSCode team.
- Github are the champions behind the electron project, with a lot of institutional knowledge about that technology + native web apps/PWAs in general. Microsoft is making a huge push toward writing UWP apps as PWAs.
Time will tell how they handle this merger. They've handled a few pretty well (Linkedin, Mojang come to mind) and others horribly (Skype, Yammer, Nokia).