We’ve heard rumblings that Warner Bros. is interested in creating a trilogy of new films that star the mallet-obsessed former psychologist, and while The Suicide Squad could certainly end up being one of those, there are several other movies in the works set to star Harley Quinn.
Nothing is set in stone yet, and it’s very possible that Harley will ultimately be back for Suicide Squad 2, but right now it’s a situation that’s very much up in the air.
The character will next be seen in Birds of Prey (And the Fantabulous Emancipation of One Harley Quinn), which began filming in mid-January 2019, and there have also been rumors of a Harley / Joker film.
Part of the reason why writer/director David Ayer isn’t coming back for the sequel is because he’s been actively developing Gotham City Sirens — and should that fully move forward, it may see the DC Extended Universe prefer to pair Harley Quinn with Poison Ivy and Catwoman instead of reuniting her with the Suicide Squad.