At PAX West 2017 in Seattle, Microsoft's Mike Ybarra, an Xbox exec, was asked if keyboard and mouse support is still coming to Xbox, and whether games other than Minecraft will be able to make use of it.
In response, Ybarra said that "keyboard and mouse support is definitely coming" but admitted that it will be "developer choice" on whether to implement it into specific games, as some games are better suited to supporting both controller, keyboard and mouse support, whereas others, particularly competitive games, are better suited to one or the other.
Mouse and Keyboard are still coming... pic.twitter.com/jbzcQvAsyS
— Xbox E3 Fans 🎮 (@XboxE3Fans) September 2, 2017
Additionally, while it is known that the new cross-play Minecraft will support keyboard and mouse input on the Xbox One, Ybarra also confirmed that other games, that they can't talk about just yet, will also support keyboard and mouse support.