It's no secret that Microsoft and Bethesda have a great relationship. Bethesda decided to show more of Fallout 4 during Microsoft's E3 2015 press conference, and mod support came to Xbox One way before PlayStation 4 players got it. That's why today's announcement isn't that big of a surprise.
They've now announced that Fallout Shelter is coming to Xbox One and Windows 10 on February 7. The game will even be a part of Xbox Play Anywhere, so you can easily change what platform you're playing on without loosing your progress.