The following contains spoilers for Thor: Ragnarok as well as, potentially, future MCU movies.
Thor: Ragnarok is the last Marvel movie to feature an Avenger prior to Avengers: Infinity War next year. As such, it sets the table for the big crossover event, but with all the characters that will be appearing, the fate of at least one is in question. The finale of Ragnarok sees Hela get pretty well smashed by the massive raging Surtur in the final moments before Asgard's complete destruction. It would seem that Hela has been destroyed, but this is a comic book movie after all, so the truth is always up in the air. That is unless you ask Ragnarok co-writer Eric Pearson, who told our own Eric Eisenberg that he has a (mostly) definitive answer to the question. Hela is dead. According to Pearson...
Surprisingly, while we might expect an answer that hedges things a bit, Eric Pearson is definitive that as far as he's concerned, Hela is dead. The point of the story was to make her a villain so powerful that only her complete destruction, brought about by the destruction of Asgard itself, would truly stop her. That happens, so it follows that she perished with the planet.
Pearson does leave open the possibility that the character could be brought back, as we never see a body, but the difference here is that, while that could happen, if it does, it will be for some as yet unconceived of purpose. As far as the script of Thor: Ragnarok is concerned, Hela is dead.
One thing this probably does is completely kill the theory that Hela will be taking a key place in Avengers: Infinity War. Some theorized that Hela would play the role in the film that was held by the personification of Death in the comic book version of the story. If Hela was appearing in either Avengers movie, which have now both gone before cameras, it's unlikely the answer would have been so clearly no.
So while it's possible that we could still see Hela again one day, we probably shouldn't expect it anytime soon.