The rumor mill is busy today. Multiple sources are claiming in 2017 Microsoft will release a new XBox, codenamed "Scorpio" with a more powerful GPU and with a 2TB drive. The new XBox is apparently capable of supporting the Rift, and Microsoft is already a partner with Oculus via their wireless controller. Since the minimum specification for Oculus is a GTX 970, in theory, a new upgraded XBox could certainly attain this level of performance.
Microsoft is already in the process of merging their XBox and Windows systems. Games such as Halo Wars and Gears of War allow gamers to interact on either platform. This would allow XBox to compete with Sony without releasing their own VR headset.
Microsoft is expected to release a smaller, more compact version of the XBox at E3 next month.