Since his discreet cameo in 2011's Thor, Jeremy Renner's Clint Barton, a.k.a. Hawkeye, has been one of the Marvel Cinematic Universe's key supporting heroes, lending his archery talents in The Avengers, Avengers: Age of Ultron and Captain America: Civil War. While there are still no plans to give Hawkeye his own movie or TV series, he's still going to be a prominent player in the MCU's immediate future. Renner is currently participating in the back-to-back Avengers: Infinity War/Avengers 4 shoot, and now it's being reported that he'll appear in Ant-Man and the Wasp, too.
The next two Avengers movies are currently taking up the majority of Jeremy Renner's time right, meaning he's unlikely to reprise William Brandt in Mission: Impossible 6. However, in its write-up of Renner's absence from the latest IMF adventure, Showbiz411 also casually mentioned that Renner will remain close to the world of Marvel by showing up in Ant-Man and the Wasp. This is currently just a rumor, and aside from Paul Rudd, Evangeline Lilly, Michael Douglas and Michael Pena all being confirmed to reprise their respective roles from the first Ant-Man movie, no casting announcements for Ant-Man and the Wasp yet. It is worth noting that the Ant-Man sequel is expected to start shooting this July at Pinewood Studios in Atlanta, Georgia; the same place where the next Avengers movies are conducting much of their principal photography. So passing Renner between both Marvel productions would be doable since they'll be in the same area.
While Hawkeye coming aboard Ant-Man and the Wasp might sound like a weird addition, let's not forget that 2015's Ant-Man threw in The Falcon for Scott Lang to tussle with when he was trying to take a device from the Avengers headquarters. It's safe to say including a guy who shoots bow and arrows would be a little easier to pull off, especially since Clint and Scott are already familiar with one another thanks to their time on Captain America's anti-registration team in Captain America: Civil War. It would also continue the trend of other Marvel heroes popping in solo movies led by different protagonists, like Iron Man in Spider-Man: Homecoming and Hulk in Thor: Ragnarok.
The last time we saw Hawkeye in Captain America: Civil War, he, Ant-Man, Scarlet Witch and Falcon had been imprisoned on The Raft, but they were later freed by Steve Rogers. Since Clint Barton has a family, no one would fault him for immediately returning to his loved ones and going into hiding with them, but his crime fighting days are far from over. He'll have to jump back into action with the rest of Earth's Mightiest Heroes when Thanos comes to Earth, and if this rumor is true, he'll also be crossing paths with the MCU's shrinking superheroes. As long as Hawkeye doesn't take too much away from Scott Lang and Hope Van Dyne in the sequel, having him pop up to show off some new trick arrows could potentially be interesting.
Ant-Man and the Wasp will be released in theaters on July 6, 2018.