For those that forget or were unaware, Microsoft is still working on bringing mouse and keyboard support to the Xbox One. In fact, they're so close that they're almost ready to announce the first title to support mouse and keyboard support.
Director for Xbox, Mike Ybarra, recently spoke at a PAX West panel and answered some questions about the progress of keyboard and mouse support for the Xbox One.
They mentioned that the feature is still coming, but they need to be careful about how they implement it. They made it clear that they understand players are concerned about the unfairness of going up against somebody with a keyboard and mouse, so they'll make it a mission to ensure developers have guidelines in place.
With these guidelines, it will be down to the developer to decide whether they add keyboard and mouse support for their games. Developers are also encouraged to give those with a controller the option to only play with other people with a controller. It'll be the same for those that have a keyboard and mouse so that players can be given an equal playing field.
For games that don't have competitive multiplayer, for example, a single player or a co-op game, keyboard and mouse support can be added without the need for a system such as the one mentioned above.
The Xbox team will give developers the opportunity to be coached on how to implement a fair system if a developer does decide to add keyboard and mouse support for their Xbox One title.