The Wrap reports that Harbour screen-tested for the role, although the actor and 20th Century Fox haven't confirmed that.
Cable's real name is Nathan Summers and he's the son of Scott Summers, aka Cyclops. Cable's known for his bionic arm and cybernetic eye and other embedded tech that lets him hack any computer. He was first introduced in a 1990 comic.
Meanwhile, we'll have to wait until October 31, 2017 for the second season of "Stranger Things."
Harbour recently appeared in "Suicide Squad" as a non-mutant, non-superhero government official and opposite Jamie Foxx in the crime drama "Sleepless." He also gave that awesome, impassioned acceptance speech at the SAG Awards that inspired all those Winona Ryder-reaction memes.