In Thor: Ragnarok, Thor is in search for his father, Odin, as indicated in the post-credits scene of Doctor Strange. 

According to speculations, Odin is somewhere on Earth and Thor needs all the help he can get, even if it includes Loki's, his wayward brother. In Thor: Ragnarok, the two will be working together. It seems that this greater problem has forced them to set aside their differences.

Odin Exiled on Earth

But it appears that it was Loki who exiled their father on Earth. Odin is now presumed to be roaming around streets of New York City as a homeless and aged man. Reports say that this theory is based on some photos of Anthony Hopkins for Thor: Ragnarok.

There are also some rumors that Odin, somehow, has lost his powers here on Earth. This will be a situation that could potentially be a lead-in to Thor's Ultimates version where he is portrayed, not as a god but a powerless earthling.

Thor and Loki to Work Together

Hopkin's recent pictures also show Thor (Chris Hemsworth) and Loki (Tom Hiddleston) on the set sporting human street clothes. There have also been speculations that they are indeed looking for Odin in New York City. But it is not yet clear what the real motives of Loki are in helping Thor. Perhaps there will be a much bigger issue that forces them to work things out together.

Who Will be Doing Cameo Roles?

Rumors have been repeatedly saying that John Cena, a WWE celebrity, and a famous movie star himself, will also make an appearance in Thor: Ragnarok. But in this case, John Cena will be appearing as himself - a WWE wrestler. Apparently, he will encounter Thor and Loki while they are desperately searching for their father in New York City.