The Razer’s edge.
Microsoft has been working towards Mouse & Keyboard support for the Xbox One for a while now. And soon, that support will finally come along. To do it, Microsoft has recently teamed up with Razer; specifically, to enable Razer’s Chroma RGB lighting support in Xbox games.
Microsoft has gone about informing developers of hat this could mean for their games, of course. That said, it’s up to said developers to incorporate those features into their games. There’s also the problem of matchmaking similarly equipped players; Mouse and Keyboard players can have a pretty big advantage over those using controllers, after all. That, too, is left to developers to sort out, though Microsoft is also offering them tools to make that easier.
As to their mouse support, Microsoft has plans to support a wide range, both wired and wireless. Though Bluetooth and custom ice won’t be supported initially, they will eventually get their update. Microsoft is also doing their best to weed out and block keyboard devices like the Xim, which mimics controller behavior to trick those sorts of matchmaking tools.