There is a popular fan theory regarding the younger version of Gamora who was brought to the present in Avengers: Endgame, and who the Guardians of the Galaxy will be tracking down in their next film. The theory states that Mantis, who can affect emotions, could also use her powers to share the old Gamora's memories with her younger self, to make her trust the other Guardians. Unfortunately, director of the series James Gunn shot down the theory in response to a fan on Twitter.
"Starting early? We SEE them work in reverse when she fills Gamora with fear. But memories are thoughts, not emotions. She cannot read or send thoughts, only emotions. #QuarantineWatchParty #gotgvok2 ok no more questions until this evening!"
James Gunn has made it clear that Mantis's powers are not going to be the way to bring Gamora back into the team's fold. After present-day Gamora was sacrificed by Thanos in order to retrieve the soul stone, the new Gamora who jumped into the present from her past timeline is a complete stranger to the Guardians of the Galaxy.
She ably demonstrated this fact by kicking Star-Lord when he tried to get close to her. As far as the younger Gamora is concerned, she has no idea who Peter Quill, Rocket Raccoon, Drax, Mantis, or Groot are, and feels no personal connection to any of them.
The only person she recognizes is her half-sister Nebula, but that is far from a warm relationship. Past Gamora had already turned on Thanos, but the Nebula of her timeline had not. The two siblings will have to start their relationship all over again from scratch to reforge the bond they had managed to acquire by the end of the second Guardians of the Galaxy movie.
The hunt for Gamora is likely going to be a large part of the next Guardians movie and the space-faring team will be joined by special guest Avenger Thor Odinson. It is not yet clear whether the next Thor movie will come out before or after the next Guardians film, and how each might affect the events of the other.
There is also the question of, now that the Guardians have fought alongside the Avengers, whether they will continue to have dealings with Earth's mightiest heroes or go back to doing their own thing. The MCU has already teased the creation of Sword, the cosmic arm of Shield, which deals with galactic level threats. It could very well be that we get to see Nick Fury recruiting the Guardians to join Sword, along with Captain Marvel and other space superheroes the franchise introduces in the future.
As big a threat as Thanos was, the upcoming characters known as the 'Celestials' whom we will be introduced to in Eternals promise to be even more dangerous for the safety of the universe. And since Quill is half-celestial, the Guardians will likely be caught right in the middle of the danger once it rears its head.