Thor: Ragnarok - 7 Predictions For The Huge Surprise
4. Loki's Double Turn
At the start of Thor: Ragnarok, it would seem that Loki will be cast off the throne of Asgard by his accidental lack of foresight to make sure Hela is safely imprisoned. He'll be forced to go with Thor to find their father, who he cast out himself, and will seemingly end up on Sakaar as a prisoner of The Grand Master too. All of that - and the Doctor Strange post-credits - suggests that he's going to be willingly working with Thor again.
But then there was a suggestion in the Infinity War footage shown at Comic Con that Loki hands the Tesseract over to Thanos, so something in the meantime is going to have to change.
The simplest explanation is that Loki defers to being Loki the minute the threat of Hela is no longer immediate to him. Once he senses he's off that hook, he could simply turn on his brother once more (he's never seemed the type to be particularly reliable in his baheviour). Or perhaps he's even working for Hela all along (which is how she manages to follow them to Earth so easily?) and the end of the film will show his betrayal once more?