Even though Star Trek: Picard has come to an end, Patrick Stewart has said that he would "never say never" to a return performance as Admiral Jean-Luc Picard, so it's good that Star Trek already has set up his perfect comeback. Picard season 3 was intended to be the end of Jean-Luc's story, wrapping up the various loose threads left by the abrupt ending to the Star Trek: The Next Generation movie franchise. As well as placing a full stop on the story of Jean-Luc's Borg trauma, Picard season 3 reconciled his reluctance to be a father, by introducing his son, Jack Crusher (Ed Speleers).
While it's unlikely that Patrick Stewart would commit to a Star Trek: Picard season 4, it's possible that he would do the odd cameo as the retired Starfleet Admiral. However, Picard's Starfleet career has been fairly well documented in Star Trek's recent history and there are other interesting stories to tell outside the institution. One element of Jean-Luc's backstory that rarely factored into Picard was his love of history and archaeology, which he pursued throughout Star Trek: The Next Generation. Picard's passion for archaeology could pave the way for his eventual Star Trek return in another 24th-century-set show.