Overwatch's competitive mode, which was cut from the game prior to release so that Blizzard could make changes based on the feedback they got on it from the beta, has been reintroduced to the PC version of the game. Now it's the Xbox One's turn.
Competitive mode is a more serious mode of play for Overwatch, "rasing the bar for competitive players". Blizzard has restricted it so that only players with a level of 25 or higher get access, so that everyone playing has a solid understanding of the game's mechanics, maps and heroes.