Gamora survived Tony's snap because she had changed allegiances when it happened. The stones can interpret the users' intentions, and Tony only snaps Thanos' invading forces. Nebula had already convinced Gamora that Thanos was in the wrong by this point, so the soul stone likely sensed that she was no longer a threat.
Once the fight is done and Thanos is defeated, everyone who came to Earth-616 with the Mad Titan gets stuck in the Avengers' original timeline. That's the case of Variant Gamora. So, the version of Gamora who currently exists in the MCU came from a different timeline and never shared adventures with the Guardians.
Why did Gamora return but not Black Widow, even though they both died in the same way? The main reason is that Gamora died in Vormir before Thanos' snap, whereas Natasha died after Thanos' snap. What is this? Further, Black Widow cannot be awakened since she has passed away and not merely due to the snap.
Gamora then came back in Avengers: Endgame as a few years younger version of herself. This was all possible because of the Avengers' time travel.
The chances are really low. Guardians of The Galaxy Volume 3 sets Gamora's return to the MCU to finish her story with a solid ending and explain what happened in Avengers: Endgame. That being said, we probably won't see Gamora played by Zoe Saldana again.
The Gamora that we met during the events of Avengers: Endgame is a different younger version of Gamora that never met Peter Quill and never fell in love with him, and it's impossible for her to have memories of the events of something that never transpired in her timeline.
By the end of Guardians of the Galaxy Vol. 3, Peter Quill and Gamora do not end up in a relationship with each other.
Endgame, however, brought Gamora back thanks to the Time Heist, allowing her 2014 self to journey to the present. After Thanos' defeat, Gamora's MCU future was left uncertain, as while the Guardians of the Galaxy returned in Thor: Love & Thunder and The Guardians of the Galaxy Holiday Special, Gamora didn't join them.
After Endgame, Gamora joined the Ravagers
This Gamora joined the cause in part because she knew that Thanos would kill her, which influenced her decision quite a bit.
2014 variant
Gamora is then brought through the Quantum Realm to the current universe and is recruited by the other Nebula to join her side. They find Nebula and Clint Barton in the destroyed Avengers Compound and try to convince her to abandon Thanos. However, she refuses, and is killed by the other Nebula.
Even if you have returned it to its original location, you wouldn't be able to get the person back. In fact, it's not really returning the stone, more like put it back properly. The tribute soul for the soul stone will forever be sealed in that place, therefore Black Widow is gone forever.”
Vision wasn't made in 2014, which is when Nat, Clint, Nebula, and Rhodes went. It's the same reason why Heimdall, Loki and Gamora also didn't came back by Hulk's snap! They died in Infinity War but not got snapped out of existence...
We know that Gamora wasn't at Tony Stark's funeral - unsurprising considering that she didn't know him, really - so she must have fled after the battle was won.
Thanos was crying because he had to sacrifice Gamora to obtain the Soul Stone. He was crying because she was the person he loved the most in the world, and he had to give her up to accomplish his genocidal plans. The fact that he was still willing to pay the price proved that he didn't love her enough.
Instead, the Gamora we will see is from the 2014 version of Thanos' timeline, who was brought to the present. The original Gamora, who tragically met her demise in Infinity War when she was sacrificed to obtain the Soul Stone, will not be making a return.
At the moment, it looks unlikely that the Guardians will come back for a fourth movie – at least in the form that we currently know them – but never say never.
Gamora Is Back in "Guardians of the Galaxy Vol. 3" — With a Major Catch. One of the most devastating deaths in 2018's "Avengers: Infinity War" is the loss of Gamora (Zoe Saldaña), who's sacrificed by her father, Thanos (Josh Brolin), so he can get all the Infinity Stones.
Black Widow star Scarlett Johansson has confirmed that she has no plans to return to the Marvel Cinematic Universe in the future.
Probably, the user may probably see the one he loves the most, or the one who was sacrificed for the Soul Stone. Gamora fulfills both the criteria. She was the one Thanos loved the most, also she was sacrificed for the Soul stone. Probably this is the reason Thanos saw her moments after the snap.
The Gamora variant encounters Star-Lord, but has no memory of him (since they hadn't met yet). After the battle, Gamora disappears. As of the Endgame finale, 2014 Gamora is off in space on her own, which is why she isn't with Thor and the Guardians.
At the end of Endgame, this Gamora did not join the Guardians and went off on her own. Peter Quill was looking at the map to attempt to find her when Thor proclaimed them the “Asgardians of the Galaxy.”
“I'm surprised that Gamora is as much in this installment because what had happened in Avengers: Infinity War,” star Zoe Saldaña explains, who reprises the character for the fifth time.
Gamora and Peter don't end up together at the end of Guardians of the Galaxy Vol 3. The new Gamora doesn't have the memories of the older Gamora and thus doesn't have her attachments.
Because she does not have a history with the Guardians, she does not reunite with them at the end of Endgame, starting her own journey while Peter Quill is left mourning his dead girlfriend while knowing another version of Gamora is in his universe.
In the end, Peter and Gamora agree that they can't pick up any romance. Peter notes that Gamora has to be herself, and he can't force his feelings on her.