The Exiles was an amazing comic with a simple premise: Sliders meets Quantum Leap. A team of 6 heroes from different universes, typically mutants/X-Men, were banded together to solve problems in different universes that had gone off their intended paths. So you would get thrown into one universes Phoenix saga, and have to make sure that Jean Grey died, or you would have to stop a group of heroes from saving the day because the butterfly effect would mean that the entire world would be doomed because of this! Without having to worry about what was cannon, characters could die and be instantly switched out on the next mission, all while a greater power decides what their goal is.
Because the heroes were thrown from the multiverse, you would sometimes get characters who were similar to their 616 (main Marvel universe), but they wer just a little different. Take Namora. She was an alternate Namor that had come from a universe wher she was a woman, still blue skinned, and had a relationship with her world’s Mr. Fantastic. Not everyone had to be gender swapped, but sometimes there were a few characters. Sometimes, the people who were not intended to be the heroes gains the power instead, so you end up with characters such as Mary Jane being Spider-Woman, or an African American Heather Hudson ending up as Sasquatch!
I loved Exiles because literally anything could happen, and no one was safe. If you get a chance, pick up some of the comics or the trade paperback books, as you wont regret it.