Photo credit: Nerdist
After a great deal of speculation, Josh Brolin has been tapped to play Nathan Summers. Brolin was rumored to be in consideration, but he was up against names like Michael Shannon, Brad Pitt, and (for some strange reason) David Harbour. With this casting, Josh Brolin enters his 4th comic film universe (Previously playing Thanos in the MCU, Dwight McCarthy in Sin City: A Dame to Kill For, Jonah Hex in a DC film of the same name)
Brolin would not have been my first choice; however, I do believe he will be just right for the role of Cable. I, for one, am looking forward to seeing how he and Reynolds mesh together in Deadpool 2. Since the film will likely go in the direction of the first film, look for multiple 4th Wall breaks regarding Brolin's comic book film past (i.e. "What happened to your face?", references to Thanos, etc.).
Deadpool 2 is set to release in 2018.