Warning: Spoilers for Avengers: Endgame below!
Avengers: Infinity War sees a heartbreaking number of our favorite Marvel characters turn to dust, and its followup, Avengers: Endgame, brings many of them back thanks to a little time travel, some timeline hopping, and a snap from Professor Hulk's (hunky?) fingers. Sadly, some deaths are irreversible, particularly ones that occurred outside the snap, like Gamora, Black Widow, and of course, Thor's trickster brother Loki.
The God of Mischief is the first to die in Infinity War, but he pops back up during Endgame thanks to the Avengers' time heist shenanigans. Tony and Scott are assigned to travel back to an alternate 2012 and retrieve the Tesseract before Thor brings it back to Asgard, along with a locked up Loki. Scott flies into Tony's arc reactor to tweak some wires that will trigger a heart attack, so he'll drop the briefcase containing the Tesseract. The plan is for future Tony, dressed in a SWAT team uniform, to sneak by and grab the suitcase, but he's swatted away when an angry Hulk crashes into him. Seeing his chance, Loki snatches the fallen briefcase and uses the stone to teleport away.
The Tesseract that the Avengers eventually use to form their own Infinity Gauntlet actually comes from the '70s, which means that when Steve goes back to return them, he didn't have to go back to 2012 and stop Loki from escaping. Which means that Loki's fate in that timeline is very much open-ended.
But of course, the sequence of events has fans wondering if there's a timeline where the adopted son of Odin might actually still be alive. According to Anthony Russo — half of the Marvel directing duo known as the Russo brothers — that's definitely a possibility. "Loki could absolutely still be alive in an alternate timeline," he told the Los Angeles Times when asked if Loki could still be out there, somewhere.
Logically, there are probably multiple timelines where Loki is still alive, as well as everyone else who has passed away by Endgame's release (yes, even Tony). But in the current Marvel timeline, Loki is still very much dead. Luckily for Loki fans, though, that doesn't mean his story is over! Loki's escape in Endgame is the perfect set-up for his upcoming Disney+ series, in which we'll see him influence historical events. So, we'll be able to see see how the trickster god's timeline unfolds in a whole new series — hopefully with exciting cameos from other heroes of the MCU!