“Every day, I come by your house and I pick you up.

[Nintex]

MOVIE ENDING AND PLOT SPOILERS
If you don't plan on seeing it but wonder why folks are dissapointed:
A) It is kinda slow and boring
B) People dislike the plot

Spoiler:  (click to show)(click to hide)

The movie musical puts Arthur Fleck on trial for 2.5 hours as it recaps the events of the first film (you'll find out what happened and didn't happen). During trial they basically revert his "Joker" persona to what he was at the start of the first movie: Arthur Fleck. He meets Harley who is "attracted" to his Joker persona. You find out most of what happened in the first film didn't actually happen. It was all in his head. 

He never lets the "Joker" out during the trial though and Arthur is gang raped by cops in jail. 
When Harley finds out he's a fraud she breaks up with him. 
There is an explosion in the courtroom that hits Harvey Dent, so that's the origin of Two Face.

In the end he is murdered by the "real" Joker. Someone who was inspired by his Joker persona and adapted it as his own. 

They hint strongly that the new Joker is the Heath Ledger Joker from The Dark Knight as he carves a smile in his own face.