Adam Warlock was first teased in one of several post-credits scenes for Guardians of the Galaxy Vol. 2 back in 2017, and it looks like the character is finally going to make his MCU debut in James Gunn's upcoming threequel.
The Illuminerdi reports that Marvel is currently searching for "a thirty year-old Caucasian man, who is described as both a super hero type and a Zac Efron type" to play the space-faring hero in GOTG Vol. 3, which Gunn recently confirmed is scheduled to begin production later this year.
In the Vol. 2 stinger, we see Sovereign High Priestess Ayesha (Elizabeth Debicki) introduce the birthing pod containing "the next step in our evolution," who she names Adam. Since Warlock plays an integral role in the Infinity Gauntlet comics, many fans assumed this was setting up his introduction in or in the build-up to Avengers: Infinity War, but that obviously never happened.
If accurate, this also suggests that Ayesha and The Sovereign will return to seek revenge on the intergalactic A-holes who stole their batteries.
All we know for sure is that the main cast are all set to return, and although Gamora was killed off in Infinity War, the character is expected to play a major role in the plot. This obviously suggests that the alternate timeline version of Gamora who was introduced in Endgame will end up joining the crew. It may also be worth noting that the green-skinned warrior has a close relationship with Adam Warlock in the comics.
Gunn is usually pretty open about debunking/confirming rumors on social media, so there's a chance he'll weigh in on this. Be sure to keep an eye out for updates.
Well, that didn't take long...