It sounds like Joker: Folie à Deux won’t be a part of any connected DC film universe the newly instated James Gunn might oversee.
Yesterday, October 25, it was announced that Gunn would co-lead DC Studios alongside Peter Safran, which will include things like DCEU movies, shows, and cartoons. However, the sequel to the 2019 box office hit Joker will exist outside of that, according to the report from Variety announcing the news.