So he says, at least
Franco played a scientist named Will Rodman who not only created the super monkey serum that allowed Caesar (Andy Serkis) to become smart enough to lead an army of apes, but inadvertently unleashed a virus that wiped out most of humanity, himself included.
He'll apparently be appearing via video, maybe apologizing to human survivors — including Gary Oldman, Keri Russell and Jason Clarke — for ruining their lives.
Originally, Franco said, “I was going to be a small part of the next one. There was one scene, between Caesar and my character, maybe even just like on a video that was left behind, but then a lot of things happened, like [former Fox co-chairman] Tom Rothman who was a big part of the first movie, left. Now Rupert's not a part of it so I don't know. My guess is I won't be in it. Nobody's talked to me since Rupert left.”