According to Ant-Man and the Wasp director Peyton Reed, the future of the MCU might very well be time travel.
“Based on the science that we’ve set up in the first movie and this one, I won’t rule out the possibility,” Reed told The Huffington Post when asked if time travel could be a factor in Avengers 4. “We are dealing with a time vortex. That could happen.”
Reed stopped short of confirming that the time vortexes established by Ant-Man and the Wasp as part of the MCU's Quantum Realm would directly factor into the future of the Avengers, but did say the Quantum Realm is "definitely a priority" in Marvel's plans.
As for what could become of Hope Van Dyne/the Wasp (should Avengers: Infinity War's "snap" be reversed, of course), Reed has a plan - leading her own all female Avengers team.
"I’d like her running things. I’d like to see her as the head of the all-female Avengers," Reed confessed. "I know Evangeline sort of said ... maybe that would be Captain Marvel, because she does have the word 'captain' in her name. But I think Hope van Dyne is a very decisive leader and a tactician, in addition to being a brilliant scientist. So she checks a lot of boxes in terms of who’s going to be running the Avengers, theoretically."