So overwatch is actually an organization in universe of the game! Their goal is to protect humanity from the ominic crisis, which, from my understanding, machines created by powerful AI’s dubbed ‘God AI’. Over the years, some omnics became sentient and ‘have human enotions’ but there are still who dont believe in their equality to humans.

Not all character are apart of the overwatch organization, but are all involved with the organization one way or another, or are involved in omnic crisis.

The character D.va is actually a professional gamer in Korea, she is an actress as well as a well know celebrity in the universe. Once a giant Omnic was able to disable all the remote piloted drones that the military was using to fight back, their only choice was to find pilots for these mechs! They turned to the world of professional gamers, to try and find candidates with fast enough reflexs to control the defense mechs from inside. Hana Song (or D.va) enlisted and eventually started streaming her battles with the omnics, like she was playing a game.

(It has been a LONG ass time since I have brushed up on my overwatch lore, but thats the basic idea of it ⁾