Microsoft had their own VR platform, called windows mixed reality, but it seems they gave up development for it like a year or 2 ago since they laid off all the devs working on it. The last windows mixed reality headset thats still even relevant is the HP Reverb G2. They still have the hololens though. They also bought a VR chatting app called Altspace VR which they shutdown a couple months ago. I don’t see them going further into VR from their past failures though until its too late.