The blog post explained that Xbox Insiders will have access to the functionality in the coming weeks, with Warframe being one of the first titles supported.
An exact date wasn't confirmed in either case, but you can expect more info will be coming November 10.
In the past, when such ideas have been floated by Microsoft, plenty of players have expressed concern over the advantages players with a keyboard and mouse will have over players using controllers. While this is still cause for concern, Ybarra suggests that handling fairness in multiplayer games will be up to the developers and Microsoft won't enforce any broad rules on the matter.
Laying down ground rules for keyboards and mice
Developers have already been dealing with this sort of thing on PC, as some games allow auto-aim when a controller input is detected but disable it for keyboard and mouse. Developers may go even further for Xbox games, with options to do matchmaking based on input methods. Some matches may be only for players using controllers, others for keyboard and mouse players, and some for mixed groups.
On top of that, Microsoft is leaving it entirely up to developers whether keyboards and mice are supported at all. Some games may be left out altogether.
While some players will surely remain staunchly opposed to keyboard and mouse support on the Xbox, others coming from a PC gaming background will likely be happy to have the precise control of a mouse in their games. This will also probably be a boon for peripheral makers, as the best gaming keyboards and best gaming mice will have a whole new customer base.