Harley Quinn’s stock has grown massively in recent years, boosted by Margot Robbie’s performance in Suicide Squad, the Batman: Arkham series and her own solo comic run. The last ten years especially have been very kind to her, seeing her grow into a major force amongst DC’s villains.
Since her creation in Batman: The Animated Series, Harley had been perpetually in Joker’s shadow (no prizes for guessing that he’ll feature later on too).
Though her obsessive love for Mistah J still comprises big parts of her characterisation, her larger than life persona has seen her outgrow him and gain agency, arcs and aims away from Joker. Thanks in no small part to the Suicide Squad comics, she’s built several popular and compelling dynamics with various other members of the DC canon separate from Joker, to the point where it could be argued she's more anti-hero than villain these days.
Even when he’s involved, there’s typically a bit more nous to it these days rather than a simple ‘she loves him even though he’s bad for her’ deal.