I left Microsoft around 2013 when the transition to Git was announced. At the time, most teams (that I encountered) used something called Source Depot. I was t

I left Microsoft around 2013 when the transition to Git was announced. At the time, most teams (that I encountered) used something called Source Depot. I was told that back in the day, MS licensed the source code from Perforce, forked it, and that became Source Depot. I do know there were some teams using TFS and I'm sure there were some smaller teams using Git too. I'm not sure how the transition went, since I left before it started, but I would bet it's still at least somewhat ongoing. Some of the people on my team that had been at MS for awhile were EXTREMELY skeptical of change.