Details about Marvel's Loki series on Disney+ have been slowly making their way online, from new character details to the inclusion of Owen Wilson and possibly Kang the Conqueror. Now there's also reason to believe that the live-action series may introduce Marvel Comics' version of the Justice League, the Squadron Supreme. The report comes from Bleeding Cool, with writer Rich Johnston admitting that's its more conjecture than a straight-from-the-source rumor. He's heard that the production team working on the Disney+ Loki series "has been ordering all manner of material, with the common thread being the appearance of the Squadron Supreme." This, to him, suggests that the Squadron Supreme may be a part of the series.
If Loki is going to see the Asgardian god of mischief traversing the multiverse, then an appearance by the Squadron Supreme wouldn't be out of the question. Though the team now exists in the main Marvel universe, the heroes were first introduced as part of alternate realities.
The team was originally conceived as a villainous group called the Squadron Sinister made up of thinly-veiled analogs for DC Comics' Justice League: Hyperion is a Superman type, Power Princess is analogous to Wonder Woman, Nighthawk is the Batman-like hero without powers, Whizzer is the speedster à la Flash, and Doctor Spectrum is the Green Lantern style sci-fi character. They're handy for Marvel to have around when it wants to have an intercompany crossover without that other company, or when it wants to tell an alternate reality tale using the archetypes established by DC's Golden Age and Silver Age heroes.
The group was reintroduced during the lead up to and aftermath of Marvel's 2015 Secret Wars event. The new Squadron Supreme is comprised of heroes from different realities that were destroyed and are now living in the main Marvel universe. Blur from the New Universe replaces the Whizzer as the group's speedster, but otherwise, the team is comprised of versions of characters from that original Squadron lineup. The group is now led by Phil Coulson and — in a kind of in-joke referencing the team's origin as analogs DC Comics characters — they now operate out of D.C.
Keep in mind that this is a rumor based on a theory and not anything concrete. We wouldn't get our hopes of seeing the Squadron Supreme in live-action too high. But it is interesting that the Loki team seems to have an interest in the group.
Upcoming Marvel Studios projects include Black Widow on May 1st, The Falcon and The Winter Soldier in fall 2020, The Eternals on November 6th, WandaVision in 2020, Shang-Chi and the Legend of the Ten Rings on February 12, 2021, Loki in spring 2021, Doctor Strange in the Multiverse of Madness on May 7, 2021, Spider-Man 3 on July 16, 2021, What If? In summer 2021, Hawkeye in fall 2021, Thor: Love and Thunder on November 5, 2021, and Black Panther 2 on May 6, 2022. Ms. Marvel, Moon Knight, and She-Hulk are also in the works for Disney+.