https://www.gamespot.com/articles/xbox-one-keyboard-and-mouse-support-definitely-sti/1100-6453087/

For a long time now, Microsoft has said the Xbox One will add support for keyboard and mouse...eventually. Now, Xbox director Mike Ybarra has confirmed that this is still coming, and in fact, we might hear about the first supported titles quite soon. Speaking at a PAX West panel this weekend, Ybarra said keyboard and mouse support is "definitely coming," adding that he's aware of the concerns people have about keyboard and mouse users having the upper hand against people using a controller.

"We have to be very smart in how we do that. We'll leave it a lot up to developer choice," Ybarra said (via WindowsCentral). "A lot of people tweet me and say, 'You can't do this because of fairness,' and we understand that. We run two platforms; the Windows platform and the Xbox platform."