There aren't a whole lot of people looking at the promotional material for Avengers: Endgame and seeing The Big Lebowski connection. And that's on purpose. Marvel Studios and the Russo Brothers did a pretty remarkable job of keeping everything in the trailers and TV spots as vague as possible, giving certain teases, which ultimately lead to nowhere when compared to what happens on the big screen. And one of the biggest and funniest reveals is the tribute to the Coen Brothers' 1998 cult classic comedy. There are MAJOR SPOILERS for Avengers: Endgame below, so read ahead at your own risk.
Ok, there are real SPOILERS coming next, so stop reading now if you haven't seen Avengers: Endgame. It's no secret Earth's Mightiest Heroes are down and depressed after the events of Infinity War, but things get even worse. Three weeks after the Decimation, the team locates Thanos and finds out he destroyed the Infinity Stones. In a fit of rage, Thor goes for the head and decapitates the Mad Titan, which sets him on a downward spiral. When we next see the God of Thunder, he looks more like The Dude from The Big Lebowski.
When the team figures out a way they can possibly reverse the Decimation, Rocket and Hulk are given the job to go hunt down Thor, which leads them to New Asgard. Valkyrie directs the duo on where to find Thor, but this isn't the Thor we all know. Instead, he has gained quite a few pounds as he only drinks beer and plays video games all day with Korg and Miek. He has a long beard, sunglasses and is dressed nearly identical to how Jeff Bridges was in The Big Lebowski. At one point in Endgame, Tony Stark even refers to him as Lebowski.
Thor doesn't seem to care about anything at all anymore, much like The Dude, at the beginning of Avengers: Endgame. He is basically an alcoholic and Rocket is only able to get him on the Benatar by revealing there is beer on the ship. Obviously, things change for the God of Thunder, but he keeps his new physique throughout the movie, adding some much-needed comedic elements to the story. It's no wonder why Chris Hemsworth is so interested in coming back to the MCU after getting to mix the God of Thunder with The Dude.
While there is a definite homage to The Big Lebowski in Avengers: Endgame, there are also some subtle callbacks to Oliver Stone's The Doors. There are more than a few times where Chris Hemsworth seems to be channeling Val Kilmer, who was channeling later era Jim Morrison in the 1991 biopic. It's going to be interesting to hear what the Russo Brothers have to say about Thor's arc in the movie and where their inspiration for certain shots came from. Hopefully Marvel Studios and the Russo Brothers will start to pull the veil back on Avengers: Endgame in the coming weeks.