As the character has been a fan-favorite since her first appearance on the episode of Batman: The Animated Series titled “Joker’s Favor”, The Joker’s on-again off-again girlfriend, Harley Quinn had a brief cameo in a Season 2, episode 16 of Arrow which was titled “Suicide Squad”. Naturally, fans (Including myself) went Batarang crazy over the mere sound of her voice.
Executive Producer of Arrow, Andrew Kreisberg was questioned about the Suicide Squad’s appearance in the episode and was asked if The Cupid of Crime will be expected to make an actual appearance in the show. To which he replied “I don’t know about that. There are very few things we’ve asked DC Comics for that we haven’t gotten. That was something you asked for, and what you saw is a compromise that Geoff Johns and I came up with. To even get that much was a thrill for us. I know that they may have other plans for her, but it was certainly an Easter egg that thrilled us. But the Suicide Squad will definitely be back. Whether we see the ‘deranged female killer’ we saw before, we’ll have to wait and see.”
Although his answer was entirely straight-forward, he did not deny if Harley Quinn will make an appearance. Even if she does not, he did say that “They” (Warner Bros.) have plans for her”. Which could mean that if she does not appear in an Arrow, it’s possible she will either appear in another series, or better yet, a live-action film!
Source(s): Comic Book Movie