Before the film came out, one Infinity Stone that managed to elude a lot of Marvel fans was the Soul Stone; and even when Thanos got his hands on it, it's abilities still weren't made clear. Thanks to co-director Joe Russo, we get a few details on how the stone actually works in the MCU.
He confirmed this during the recent Q&A (via Collider):
"The Soul Stone obviously has the ability to manipulate your soul, the essence of who you are. One key moment where it's used is where Doctor Strange turns into multiple Stranges and then Thanos uses the Soul Stone to eradicate all the fake Stranges and momentarily shoves Strange out of his own body, and Strange has to pull himself back in… Of course when Thanos goes to the Soul Stone itself, to speak to his dead daughter, he obviously has an ability to resurrect, conjure the spiritual representation of the people who are dead."
While a lot of people were convinced that the Soul Stone was actually the one in Loki's scepter, it was proven ultimately to be the Mind Stone. I do still think it's interesting that the Soul Stone could bring people back from the dead. Then again, how come it's young Gamora that shows herself to Thanos and not the older one which he threw off a cliff?
For now, it looks like Thanos is content with finally being able to genocide half the universe. We don't know if the Gauntlet and the stones will still be able to function for now, but Thanos did use it to escape Thor and fix himself up. Maybe he still has access to them in the sequel?
A lot of fans were ultimately disappointed that Marvel didn't drop any A4 trailer for November, but I'm sure it's going to come out sometime before the year ends.
Catch Avengers 4 in theaters May 3, 2019.