Do you know that team-based multiplayer online first-person shooter video game?
No but I would love to learn about it
The game was made/ developed and published by Blizzard Entertainment
Its multiplayer so how many teams or players can compete?
It was made available on all platforms including windows and xbox on in May 2016 
So its relatively new, is it very popular?
team work together to secure and defend control points on a map or escort a payload across the map in a limited amount of time. Players gain cosmetic rewards that do not affect gameplay, such as character skins and victory poses, as they play the game. The game was initially launched with casual play, with a competitive ranked mode, various 'arcade' game modes, and a player-customizable server browser subsequently included following its release. Additionally, Blizzard has added new characters, maps, and game modes post-
Overwatch (video game)
Overwatch is a team-based multiplayer first-person shooter developed and published by Blizzard Entertainment and released on May 24, 2016, for PlayStation 4, Xbox One, and Windows. Described as a "hero shooter," "Overwatch" assigns players into two teams of six, with each player selecting from a roster of over 30 characters, known as "heroes," each with a unique style of play that is divided into three general roles that fit their purpose. Players on a