Microsoft has updated their Wireless Display app for the Xbox One that allows for streaming of PC games to your console. If you've got some PC games you want to play in your living room, the app will use Miracast technology to let you stream it to your Xbox One.
Currently, you can only use a controller to control your games so no keyboard and mouse support right now. Hopefully, that comes in at a future patch.
We've seen this technology on Android and PC using Valve's own Steam app or an open source software like Moonlight that takes advantage of NVIDIA's Gamestream tech. Now, the Xbox One can also do it as well.