The Collector seemed to be dead well before the ending of Avengers: Infinity War, but is the immortal really gone for good? First encountered during a brief post-credits scene in Thor: The Dark World, the Collector soon became an important player in the MCU’s convoluted mythology. Living up to his name, the flamboyant Benicio del Toro character was later properly introduced via a handy piece of exposition in which he expounded on the use and value of the all-important Infinity Stones.
The scene, which occurs in 2014’s Guardians of the Galaxy, shows The Collector’s Marvel Easter Egg-filled museum and made it seem clear that his collection will have a profound effect on the action of the series. After all, that initial post-credits appearance at the end of Thor: The Dark World seemded to suggest he was looking to bring the Infinity Stones together himself. There was no suggestion he was working with Thanos at that point and then Avengers: Infinity War seemed to suggest the Titan killed him off.
But is The Collector really dead? The Infinity War Reality Stone sequence that revealed Thanos' trick certainly suggested a battle had occurred, but that's not necessarily definitive. Actor Benicio Del Toro may insist that the Collector is alive, but his jovial “he’s alive—you’re talking to him!” during an interview could pretty reasonably be read as a joking bit of trolling by the genial thespian. Or was it?
Despite del Toro’s characteristic inability to take the question seriously, the fate of the Collector is actually one of Infinity War’s biggest loose ends. While it could be that the Eternals will reveal the origin of the Soul Stone’s rules, there's no confirmation that the Reality Stone requires someone to be dead in order for the wielder to impersonate them. As such, the Collector’s fate is still a mystery that may never be properly explained. In the comics, the Collector is an Elder of the universe and therefore immortal, so it may be difficult to accept that he was killed by Thanos either during the Snap or beforehand when he stole the Reality Stone. And if he was snapped out of existence, which isn't quite the same as death, the reversal would presumably mean he was alive.
Not to put too much faith in del Toro’s take, but it seems unlikely that even Thanos could kill an immortal being, particularly offscreen. Add to that the fact that Kevin Feige wants a Collector and Grandmaster movie, and it seems there's evidence to suggest he's alive. Even though the character vanished, the idea of a standard murder doesn't quite work if you choose to accept that the MCU Elders - who also include The Grandmaster - are immortal as their comics counterparts are. And as evidence there, Jeff Goldblum claims The Grandmaster is 14 million years old. Then again, there could be the chance that the Elders are not invulnerable even with the ability to live a hugely long time. Ego was an Elder in the comics (though he calls himself a Celestial in the MCU, he's not an entirely reliable source) and he was killed. So that much is up for debate.
WHILE THE COLLECTOR WAS DEFEATED AND CLEARLY DID HAND OVER THE REALITY STONE, BUT THAT ALONE IS NO GUARANTEE THAT HE’S DEAD AND GONE.The Collector
IS, AFTER ALL, A CANNY NEGOTIATOR AND, AS THANOS REMARKS DURING THE ILLUSION, THERE'S NOTHING HE WOULDN'T DO TO ADVANCE HIS OWN AGENDA. COULD THAT REMARK BY THANOS SUGGEST TANELEER SHOWED DISHONOR IN GIVING UP THE REALITY STONE, EARNING THANOS' DISGUST? COULD HE HAVE BEEN TRICKED? THERE’S NO WAY TO KNOW FOR SURE WHETHER THE COLLECTOR WILL PUT IN ANOTHER APPEARANCE IN THE MCU BUT BETWEEN HIS STATUS AS AN IMMORTAL AND ENDGAME’S ALL-IMPORTANT SNAP REVERSAL, IT FEELS FAIR TO GUESS THAT THE COLLECTOR IS STILL OUT THERE SOMEWHERE, DESPITE THE DESTRUCTION OF HIS COLLECTION INAVENGERS: INFINITY WAR