https://www.gamespot.com/articles/xbox-one-gaining-mouse-and-keyboard-support/1100-6462040/

Microsoft has announced that Xbox One consoles will soon enable mouse and keyboard support. The company followed up with another announcement that it would be partnering with Razer to bring players additional mouse and keyboard options.

In the announcement, Microsoft added that mouse and keyboard support would be case-by-case with the choice of implementing it completely up the developers. No update is going to add mouse and keyboard support to every existing title on Xbox One. Developers will either need to patch in an update or include it in future games.