"Four generations of gaming: Our commitment to compatibility means existing Xbox One games, including backward-compatible Xbox 360 and original Xbox games, look and play better than ever before. Your favorite games, including titles in Xbox Game Pass, benefit from steadier framerates, faster load times and improved resolution and visual fidelity – all with no developer work required. Your Xbox One gaming accessories also come forward with you."
I also appreciate that Microsoft is keeping compatibility with Xbox One hardware as well because typically console makers love to lock you in for a whole set of new peripherals. I've been considering the choice between Sony and Microsoft for some time in terms of a new console and unless Sony comes back to the compatibility fold I might stick with Microsoft for the foreseeable future.
For the entire info dump on the new stuff coming to the Xbox Series X head over to xbox.com below: