Continuity and the logistics of the shared universe in DC's movies can be a tricky thing to figure out, especially now after movies like Aquaman, Wonder Woman, and Shazam have done their best to pivot away from the old and start something new--or, well, sort of new. DC certainly isn't building their films out based on the MCU's blueprint, but they're also not completely scrapping their early attempts in favor of complete reboots, either.
Birds of Prey exists in that not-a-reboot middle ground. It is a sequel to Suicide Squad, in that one takes place after the other and they both feature the same version of Harley Quinn. But Birds of Prey is a Suicide Squad sequel the same way Aquaman is a direct sequel to Justice League--meaning it only really needs you to remember the tiniest handful of details from Suicide Squad to understand the plot. Can't remember who Suicide Squad's bad guy was? No problem. Don't exactly recall why or how Harley even wound up on that team? Don't worry about it. It's fine.
Harley kicks this movie off by announcing that she and the Joker have broken up while providing some rapid-fire exposition regarding her personal origin story. Most of this is done with brand new animated scenes covering her time as a child, going to college, working at Arkham, and so on. However, when it comes time to actually explain her relationship with the Joker, Birds of Prey actually pulls footage directly from Suicide Squad to cover it. The scene where she takes a swan dive into a vat at Ace Chemicals is reused, but cut slightly differently to keep Jared Leto's Joker mostly out of frame. In fact, the back of his head is all we see of Mr. J for Birds of Prey's entirety.
Birds of Prey & DC News
The actual details of what Harley and Joker have been doing between then and now are left completely up to the imagination. Tiny details like Joker's reasons for ending their relationship, how Harley managed to get out from under Amanda Waller's thumb and stay out of prison, and where Joker is now are never actually explained. As far as Birds of Prey is concerned, Harley has been galavanting around Gotham causing chaos with Joker until very recently and now they aren't anymore. We can assume that Joker is still in the picture somewhere--other characters certainly seem to be afraid of him as if he's still at large--but he otherwise never factors into the story.
Birds of Prey's only other Suicide Squad connection comes in the form of an Easter Egg during Harley's big police station blow out. As she leaves, she spots a wanted poster for none other than Captain Boomerang (played by Jai Courtney in Suicide Squad) and pauses long enough to say "hey, I know that guy." This doesn't tell us much about what Boomerang has been up to since his Suicide Squad days, obviously, just that he's still at large--but we can assume we'll get more info when Courtney reprises his role in the upcoming James Gunn Suicide Squad. Maybe he and Harley will get to have a nice catch-up chat before they're both thrust into whatever mortal peril they'll be facing this time around. (Check out our gallery for more Birds of Prey Easter eggs.)
Birds of Prey and the Fantabulous Emancipation of One Harley Quinn is in theaters now, and according to our review, it's a "top-tier" action film with a "fantastic ensemble cast." The Suicide Squad will hit theaters on August 6, 2021.