Joe Goldberg appears to murder Peach Salinger in You season 1, but there are hints that the character could return in season 4. Shay Mitchell's Peach Salinger was a constant problem for Penn Badgley's Joe Goldberg in You season 1. A close friend of Elizabeth Lail's Guinevere Beck, Peach was manipulative, toxic and kept Beck in a constant state of co-dependence. She was also jealous of the attention Beck gave Joe and wanted him out of her life. Joe, who's a murderous manipulator himself, returned her disdain. In season 1, episode 6, Joe finally gets the best of Peach, seemingly shooting and killing his season 1 rival after the pair struggle over a gun. He also stages the scene to look like a suicide.
In You season 3, Joe continues his murderous ways. Penn Badgley's character faces off with his wife, Victoria Pedretti's Love Quinn, in the You season 3 finale. In the episode, Love uses wolfsbane on Joe to paralyze him, but Joe secretly takes an antidote before his wife's killer scheme. Joe eventually surprises Love by sticking her with a syringe full of wolfsbane, which kills her. He then stages the house to look like another suicide. Finally, for good measure, Joe fakes his own death before heading to France and searching for his new obsession, a librarian named Marienne (Tati Gabrielle).
Though it appeared that Joe killed Peach in season 1, there's a chance she may return. Following Peach's supposed death, theories sprung up that the character could still be alive. After struggling over a gun, Peach supposedly dies off-screen and becomes another of Joe Goldberg's murder victims. However, the series doesn't show her death scene, leaving the possibility that Joe didn't fatally shoot her. Additionally, Raj (Gerrard Lobo), a medical student, was in the house with Peach the night before. He could've potentially helped Peach if Joe shot her. Furthermore, Peach made plans to move to Paris, which is where Joe ends up at the end of season 3.
You season 4's setup may hint at Peach's comeback. In season 1, episode 6, Peach plans to move to Paris before Joe seemingly murders her and stages it as a suicide. So You season 3 ending in Paris could be a significant clue to her return. You often plays the long game, leaving hints of where the show will go in the future. For instance, the series teased how Joe would murder Love in season 2 before he went through with his wolfsbane plan in season 3. So the series continuing in Paris may not be an accident. Interestingly, Netflix's announcement for You season 4 (via YouTube) also included a clip of Peach, showing a scene where Joe had previously failed to kill her. With the show setting up Peach's move to Paris before her death, You could bring her back to make Joe's life difficult in season 4.
The series would have to pull off some tricky plot acrobatics to make Peach's survival convincing. In season 1, the series doesn't show Peach's death scene, but it does have coroners removing a covered body from the premises. However, You has had fake deaths before, even showing Joe's ex Candace (Ambyr Childers) returning from the dead at the end of season 1. Plus, Joe is an unreliable narrator, which lends itself to the show's many twists. Whatever the case, Joe is searching in Paris at the end of season 3, and there's no telling what he may find in You season 4.