Chukwudi Iwuji is right; unless a character's death is explicitly shown on screen, there's every chance that that character is not in fact actually dead. That's just the law of Hollywood storytelling. As for Iwuji's comment about the multiverse deleting any chance of narrative permadeath, he's right on that front, too — but let's not jump to Kang-clusions just yet.
Instead, let's focus on just one universe, the one seen in James Gunn's film. "Guardians of the Galaxy Vol. 3" took the time to have Rocket Raccoon prevent the High Evolutionary's death at the Guardians' hands, so Iwuji's tacit endorsement of his character's potential future in the MCU isn't quite as subtle as all that.
So, if the High Evolutionary is still alive, where could he reappear in the MCU? The obvious and easy way to have the character return without any lasting consequences would be to have him crop up somewhere in an upcoming season of "What if ... ?" on Disney+ but, again, that dips into multiverse territory. For all the narrative significance the show entails, the animated Marvel anthology could feature Winnie the Pooh as the next Black Panther and it would carry the same heft.
A more interesting place for the High Evolutionary to appear would be in "Avengers: Secret Wars," which is basically an all-out brawl between Marvel's entire character roster. The 2015 version of the comic run features a heavy dose of the High Evolutionary, too, so Marvel could run with Iwuji's sudden spike in popularity and give him a chance to wreak havoc on a broader scale.
Just as long as the studio doesn't build its entire brand around his future. That was a bad idea the first time around, too.
