I love Overwatch, Its a video game that was released on May 2016 for Windows, PlayStation 4, and Xbox One in case you didnt know. 
That's cool! How is it played?
Well basically the game assigns players into two teams of six, with each of the players selecting from over 20 characters, known as "heroes", each with a unique style of play, whose roles are divided into four general categories: Offense, Defense, Tank, and Support.
So it's like League of Legends then?
Not really, But I see why you might think it, Overwatch is a first person shooter and is fast action and its important to pick the right hero for the game. 
It sounds like a game I might like. Is is pretty competative?
It sure is people on both teams must work together to secure and defend control points on a map or bring a payload across the map in a limited amount of time, Its very fun and very competitive. 
Are their professional teams that play overwatch?
Yes there sure is, some of which are the London spitfire and the new york excelsior's. There is so many teams that play and especially for a cash prize.
Yeah it's crazy how popular professional video gaming has become!