Uuuh, last movie I saw in theaters? It might be telling that I can't completely remember.
Well, I guess it was Black Panther. It was alright. I'm pretty big on the Marvel Cinematic Universe as a whole, seen most of it, and Black Panther is pretty average as far as solo hero films go. It didn't really have a second act, it was more like the first and third act just kinda bled into each other. T'Challa's pretty cool, but the movie definitely doesn't deserve to have made more money than The Avengers as far as I'm concerned. You want a good superhero flick, get The Avengers on Blu-ray, not Black Panther.
Oh yeah, I also saw the re-release of The Dark Crystal in theaters pretty recently. Dunno if that counts, but you should definitely watch The Dark Crystal over Black Panther if given the choice. It's real good, really different and original, fantastical, incredible technical achievement with all the puppets, possibly my favorite film ever. It also just got a 4k Blu-ray release, which you should definitely buy.