Returning player

Hi r/Tyranids I've been away from the game for quite a while mostly played 4th gen and a bit of the beginning of 5th gen. Recently started following this Sub and have been thinking about getting back into the game however it seems like a whole lot has changed since i last played (hive tyrants fly now, damn) just wanted to know what the games like now and what type of play is still relevant wasn't sure this was the best place to put this but figured id put it here since I've only ever played Tyranids and still have quite a few of my old models so they'd would be what id be going in with. Any advice would be really appreciated.