Currently, Outlast, the survival horror developed by Red Barrels Games, has only been released on PC and PlayStation 4 (free for PS Plus members), but a possible port to Xbox One has been rumored since January.
This week, Outlast has been rated for Xbox One in Germany.
You can check the USK website to see the register.
We will have to wait an official statement from Microsoft or Red Barrel Games to confirm it.
Thanks, OnlySP