Following his death in Avengers: Disassembled, Clint was reborn in an alternate reality created by the Scarlet Witch, who was also responsible for his previous demise. When the Witch's "House of M" reality was reverted back to normal, Clint found himself once more among the living, in the real world. Rather than pick up right where he left off, he let go of his Hawkeye identity, which had been taken on by the Young Avenger Kate Bishop in his absence, opting instead to search for closure and direction.
In 2007's New Avengers #30, by Bendis and artist Leinil Francis Yu, fate brought Clint to Doctor Strange's doorstep. There, he met not only with the Sorcerer Supreme, but also the New Avengers: Luke Cage, Iron Fist, Jessica Jones, Spider-Man and a few others. The heroes let Clint know that they were leaving for Japan, a rescue operation to save Maya Lopez from Elektra and The Hand. While Clint was hesitant to join them at first, he stated that his goal was to keep fighting the good fight, because that was what Steve Rogers/Captain America -- who was himself dead at the time -- would have wanted. He joined the new team of Avengers, but not as Hawkeye. Instead, he put on Maya's costume and became Ronin.
It was a new identity for Clint Barton, as he embarked on a new, different path of self-discovery. No longer was he battling with a bow, but with his fighting skills, swords and various other weapons. It was a path that led to him becoming the leader of the New Avengers, a member of the hopeful, makeshift family. Clint's stint as Ronin would last a good while, lasting through several Marvel Comics events including Dark Reign and Siege. It wouldn't be until the onset of the new Heroic Age in 2010 that he would once more call himself Hawkeye.
So what does that mean for Jeremy Renner's own take on the marksman Avenger? If Barton is to don the Ronin costume in Avengers 4, where does that leave him at the end of Infinity War? To answer that, it's important to consider what we know of the MCU's Hawkeye. Not only did he start off as S.H.I.E.L.D. agent with a penchant for bows and arrows, we also know that he has a life away from the Avengers, in his farmhouse with his wife Laura and their three children, all of whose existence remain a secret from the government. Although Clint retired after Ultron's attack on the world in Avengers: Age of Ultron, it didn't take long for him to suit back up when Captain America needed his help in Civil War. For his actions, Clint was arrested, and later broken out of The Raft prison facility by Steve Rogers.
This likely means that when next we see Barton, he will be on the run from the authorities. It's a safe bet that he will choose to say away from his family, for fear of exposing their identities and risking their safety. But all of that might prove moot when Thanos comes down from the sky, wreaking havoc on the world as he searches for the Infinity Stones. With such powerful cosmic relics in play, with such devastating raw power, it's entirely possible that Clint could be dead at Thanos' hand by the end of Infinity War, only to be brought back to life by Wanda's own powers, or something like the Time Stone.
Will Clint see fit to don a new costume as he embarks on a new mission? Could the former archer run into Doctor Strange, Spider-Man, Luke Cage, Iron Fist and Jessica Jones, an unlikely group of heroes in need of further help? Or will Clint simply prove to be in the Ronin guise from the get-go, at the onset of Infinity War, adopting a new secret identity as he continues to fight the good fight on the run from the authorities while attempting to protect his family?
Debuting May 4, 2018, Avengers: Infinity War is a production of Marvel Studios directed by Joe and Anthony Russo starring Robert Downey Jr., Josh Brolin, Mark Ruffalo, Tom Hiddleston, Chris Evans, Chris Hemsworth, Jeremy Renner, Chris Pratt, Elizabeth Olsen, Sebastian Stan, Benedict Cumberbatch, Paul Bettany, Samuel L. Jackson, Cobie Smulders, Benedict Wong, Zoe Saldana, Karen Gillan, Vin Diesel, Dave Bautista, Pom Klementieff, Scarlett Johansson, Tom Holland and Anthony Mackie. Avengers 4 is expected to hit theaters on May 3, 2019.