Earlier today, there were reports that DC and Warner Bros had officially signed off on Joker sequel. However, Deadline reports that this is a "flat false", there were no deals or any negotiations with director Todd Phillips or his co-writer Scott Silver.
THR originally reported that a week after Joker‘s massive opening, Phillips spoke Warner Bros film chief Toby Emmerich to pitch a portfolio of DC character origin stories. According to Deadline:
"No one is saying a Joker sequel won’t happen someday. But multiple sources said nothing has happened yet, and that Phillips and co-writer Scott Silver have made no real moves to draft the further dark rise of Joaquin Phoenix’s Arthur Fleck character, or even to make a deal to do that."
Joker sequel will eventually happen someday, the fact that the film earned $1.02 billion and the most profitable comic book movie of all time. Joaquin Phoenix and Phillips have recently stated that there are possible ideas for Joker 2 to work on, so the door is not completey close for the sequel.