According to giantfreakinrobot, the source that has been fairly accurate with Marvel leaks, Tom Hiddleston is joining the cast of Deadpool 3, presumably playing Loki, the trickster god. As for how Loki ends up in the film, Giantfreakinrobot suggests the post-credit scene in Deadpool 2 would make Wade Wilson the perfect candidate for the TVA to target in Loki’s first season.
As we already know Hugh Jackman will reprise the role of Wolverine in Deadpool 3, and the actors themselves, Reynolds and Jackman, have confirmed that Deadpool 3 has no connection to Logan 2017. Therefore, it appears Ryan Reynolds’ Deadpool will travel from his slice of the Multiverse to Earth-616 in the MCU, rather than retconning things to incorporate Fox X-Men movies into the MCU narrative. Therefore, Tom Hiddleston’s Loki may be essential to Deadpool 3 in this regard.

On the other hand, the popular Marvel scooper DanielRPK claims Loki’s pivotal character Agent Mobius will also appear in Deadpool 3, which has led many fans to speculate that Deadpool 3 will include some interdimensional action. In 2021, Wilson joined Loki, Tom Hiddleston’s trickster antihero, and became one of the most popular characters in the MCU.

Disney+ confirmed the return of Agent Mobius and the entire cast in its second season. Season 1 of Loki ends with the original arc Loki land in an alternate timeline of Time Variance Authority with Wilson’s character having seemingly never met him.
Tom Hiddleston promises fans that Season 2 will see the character go up against the very organization that gave him a second chance. “A battle for the soul of the TVA,” Hiddleston said.