@lostn: I don't know. RDJ & Chris Evans' contracts are up soon. Evans said himself that Avengers 4 will be his last one. Neither of them have another solo movie announced. And at least with Captain America, they have options for replacements in Bucky and Falcon. It'd make narrative sense for Bucky to take over. It feels like they've been building him up for the role, like when he took the mantle in the comics. Maybe Rhodey could replace Iron Man. With all that, I could see one or both of them biting it. Tony especially because Iron Man started it all. Infinity War is the culmination of everything they've built up to. It would make sense that this particular chapter ends with him.