The next new character in Overwatch is expected to be Doomfist. According to a persistent rumour, the voice work will be done by the actor/comedian Terry Crews. He is best known for his career in the NFL , as well as appearing in The Expendables series.
Crews visited Blizzard in mid-December and Facebook, and shared a photo of himself in front of an Overwatch banner, calling it his favourite game. As revealed in the trailer below, we also know that Blizzard has another Overwatch hero that should be moving into full production soon (and they're also playing around with various prototypes). Given what we know, the timing for this and Crews' potential appearance in the game certainly lines up.