Gamora Will Be Rescued From the Soul Stone
As we know, Gamora is Thanos's sacrifice to gain the Soul Stone. In the comics, the Infinity Stone's power is over life and death, and it works by capturing a person's essence and storing it in the Soul World, a plane that exists in the stone itself. The owner of the Soul Stone is also able to release any souls captured within it and enter the Soul World at will. If the MCU follows the comics, that explains the dream-like scene at the end of Infinity War when Thanos speaks to a younger version of Gamora after he's wiped out half the universe's existence. This also means that Gamora's soul is still around and thus can be rescued!
Despite the fact that Thanos sees Gamora as his loved one, we don't see him letting her soul out of the stone anytime soon. The best bets for this happening are either someone else's soul being exchanged for her freedom or the destruction of the stone entirely. We're betting the Russo brothers go with the more emotionally tragic option and someone else will die before we get Gamora's soul out of the stone.