James Gunn recently said that Guardians of the Galaxy Vol. 3 will set up a new version of the MCU for the next 10 years at least. One of those new movies will tell Rocket Raccoon's troubling backstory according to Gunn. And this version of the story will differ slightly from the original comic book origin. Rocket is clearly a fan favorite and an indispensable member of the Guardians of the Galaxy, so much so that Star-Lord told him that, "you have the best tactical mind I ever met."
After the events of Avengers: Infinity War, Avengers 4, and Guardians 3, we should get a more in-depth look into Rocket Raccoon's backstory. James Gunn recently spoke at Hasbro HASCON where MCUExchange reports that the director spoke about the future of the characters in Guardians of the Galaxy. A fan asked Gunn about Rocket and Gunn revealed that his story will be told, but that it would be different from the comic books. Gunn had this to say.
"As you know, the MCU is one way of processing these characters. 616 is a different one. We are going to learn more about where Rocket comes from in the coming sagas. It's going to be a little different from the comics. We already know a lot about from where he came from. It's a little bit more horrible than what it is in the comics when you come down to it. We will learn more about that."
Rocket is a genetically modified Raccoon with a love of violent weapons and a tough personality (though sometimes sensitive) due to his troubled and tortured past. In the comics, he was originally experimented on to become a Chief Law Officer on Halfworld, which was a colony for the mentally ill. He and his friend, Wal-Rus, protected the planet and its inhabitants from any potential threats, including the villainous mole, Judson Jakes and met up with Hulk for a bit before Hulk returned to Earth. Rocket managed to cure some of the colony on Halfworld of their mental illnesses and then joined the Guardians of the Galaxy.
Gunn has had to defend himself against the changes that he made from the comic books for the big screen adaptation of Guardians of the Galaxy, but the director stands by his decisions. Rocket definitely has a story to tell and at this point, the movies only go as far as to say that he was genetically modified to be stronger, but we don't know why. Gunn has only said that his version of Rocket's origins will end up being worse than what we have read in the comics, which is already pretty bad on its own. At any rate, we're still a long way away from actually getting to see more of Rocket's origins, but it is assumed that Guardians of the Galaxy Vol. 3 will touch on some more of the story, possibly setting up a standalone movie.
Until then, we'll get to see Rocket Raccoon in Avengers: Infinity War and Avengers 4, but it is pretty unlikely that we will get much of his backstory within those movies. It will be really interesting to see if the Guardians of the Galaxy pop up in Thor: Ragnarok as rumors have suggested. It would be a cool way to nod back to the comics if Rocket is able to meet up with Hulk before Infinity War and set Thor up with the Guardians as well. At this point, we'll just have to wait and see.