It was confirmed during Marvel Studios' Hall H panel at San Diego Comic-Con that the upcoming Disney+ TV show Loki will follow the version of Loki who escaped with the Tesseract during Avengers: Endgame. The Loki we've followed since the end of The Avengers, and who fought alongside Thor during Ragnarok, is still dead, having been killed by Thanos at the start of Avengers: Infinity War.
Loki will arrive on Disney+ in spring 2021, with Tom Hiddleston reprising the role that he's previously played in six Marvel Cinematic Universe movies, starting with his breakout role in 2011's Thor. The TV series will see Loki jumping around in time and playing surprising roles in major historical events on Earth. A previously-glimpsed teaser image showed Loki against a backdrop that included the theatrical release of Jaws, indicating that at least one episode will be set in the 1970s.
Originally starting out as a villain, Loki eventually came to be an ally for Thor, starting in Thor: The Dark World and continuing through Thor: Ragnarok and Avengers: Infinity War. As the Norse god of mischief, Loki has always been a trickster (as seen in Thor: Ragnarok, when Thor discovered him posing as Odin and ruling over Asgard). Loki's final act was an attempt to trick Thanos by pretending to be his old backstabbing self - a gambit that failed and ended with Loki being murdered by Thanos. That nobler version of Loki isn't the one we'll be seeing in the TV show, however; instead, we'll be seeing the version of Loki who just attempted a failed takeover of Earth with an army of Chitauri.
In Avengers: Endgame, Captain America and Iron Man go back in time to retrieve the Tesseract from 2012, but fail when Hulk bursts out of a door and knocks the Tesseract out of Tony Stark's hands. It slides over to Loki, who picks it up and uses it to teleport himself away. Avengers: Endgame's time travel and timeline elements are confusing, but now we have confirmation that the changes the Avengers made when they visited the past did in fact create alternate timelines. That means that there's a universe out there where a villainous Loki still has his hands on the Tesseract - a pretty alarming thought.
It's actually been confirmed that Loki was being mind-controlled by Thanos during The Avengers, so perhaps he won't be quite so power-mad now that he's out of Thanos' grasp. Still, the prospect of a TV show that explores that happened to Loki after he popped out of Avengers: Endgame is pretty intriguing, and we can't wait to find out more.