Pyro region Natlan is out (and concluded recently I think). So new characters, weapons, artifacts, etc. The Natlan characters have this gimmick that allows you to traverse terrain in different ways.

There's a new mode called Imaginarium Theater which is like Spiral Abyss but instead of having only 2 teams, you're given a pool of (mostly your own) characters that you can pick to build a team out of per chamber. The enemies are much easier though.

Other than that, mostly limited time events. Summer, Lunar New Year, and other events I couldn't remember anymore lol