Arena on Xbox Live is available for Killer Instinct and World of Tanks. We're just getting started—more Arena games will roll out soon.
Killer Instinct tournaments can be played from an Xbox One console or a Windows 10 gaming PC, and in cross play (if you’re on Xbox One, compete against players on PC, or the other way around). On your Xbox console or Xbox app on Windows 10, join tournaments in the Killer Instinct game hub or in a club. Get Killer Instinct free from Microsoft Store.
Currently, World of Tanks tournaments are organized by ESL. Before you can compete, there are a few one-time things to do in ESL—see Set up an ESL account for more info. Get World of Tanks free from Microsoft Store.