Yesterday Microsoft rolled out backwards compatibility for about 100 games and South Park: The Stick of Truth is one of them!
Here are two ways to get the game on your Xbox One:
1. Insert your Xbox 360 disc of South Park: The Stick of Truth into your Xbox One. It should be automatic and not cost you anything more!
2. Buy a digital copy of the game from Xbox Marketplace, then download it on your Xbox One and Xbox 360.
And make sure you check out the announce trailer for our all-new game South Park: The Fractured but Whole.
See more info about compatible titles here.