Frank Grillo made his debut as Brock Rumlow in Captain America: The Winter Soldier, and Rumlow promptly blew himself up in the sequel, Civil War. Though Rumlow may be gone, he was still able to make a return in Avengers: Endgame, but what's interesting is, Grillo is actually signed up for five more MCU films.
Talking to ComicBook, Grillo was asked if whether we could see a return of Crossbones since Marvel is moving into nonlinear storytelling territory. Grillo replied:
"You know what? I got five more movies that I'm obligated to do for Marvel if they ever call me. So who knows, man? Maybe I'll be Captain America after Mackie. I'll be a middle-aged Captain America. A middle-aged, Italian, Captain America. Think about that."
While the Captain America bit was obviously a joke, some people actually took it out of context and thought that Grillo was saying that Rumlow wasn't dead. Grillo then went on to Instagram to confirm that the character was indeed gone, so if we ever get to see him again, I'm guessing it's going to be in some sort of flashback. Who knows, maybe we can see how Rumlow is hired by HYDRA in the Black Widow movie?
If anything, fans are still waiting on the release of the slate for MCU Phase 4. After the massive undertaking that was The Infinity Saga, I think Marvel has afforded to give the fans some more experimental takes. I mean, how long do we wait for the MCU's version of Joker?
For now, you can catch Grillo in Avengers: Endgame still in theaters.