According to a post by Microsoft blogger Brad Sams, he claims to have heard from his sources that come E3 2016, Microsoft will be taking the wraps off new Xbox hardware. Given that E3 is probably one of the biggest gaming events of the year, if not the biggest, this should hardly come as a surprise.
In terms of what the new Xbox hardware can offer, Sams did not offer up much information but with the rumored PS4.5 supposedly allowing 4K gaming, hopefully Microsoft will be able to match that. Sams also notes that there will be a new standard controller shipped with the new Xbox hardware, but from what he says it sounds like it will be more of a color variant than a redesign of the current controller.
On the software side, Microsoft is said to be exploring the idea of a connection between the PC and the Xbox One. As it stands, Xbox One to PC streaming is possible, but Microsoft has made no secret that they are interested in the reverse as well. In any case take it with a grain of salt, but hopefully more will be revealed at E3 2016 in June.