In a strange turn of events, two platform-holders have competing arrangements with a property that neither probably cares about anymore.
After acquiring Insomniac Games last month, Sony finally confirmed that it now has the rights to all of Insomniac's wholly-owned properties. This includes 2014's Sunset Overdrive which was an Xbox One exclusive until it was ported to PC last year. It seems as though Microsoft still has publishing rights while Sony owns the actual IP.
Speaking with Japanese publication Inside Games, Sony Interactive Entertainment president Shuhei Yoshida said "SIE holds the rights to past Insomniac Games works." Sony doesn't seem to have interest in working out some sort of agreement to port Sunset Overdrive to PS4. Yoshida added "I am looking forward to future titles."
Navigating a PS4 port would be tricky given that PlayStation and Xbox are direct competitors. Further, a sequel is probably unlikely given that Sunset Overdrive didn't sell particularly well. Sony bought Insomniac to keep pumping out Marvel's Spider-Man and Ratchet & Clank games. Sunset Overdrive is something that could technically be revisited, but it's almost certainly low on the list of priorities.