So if that’s something you are looking forward to, it will be coming along with Season 4. Though it’s only a pipe dream now, creator Roberto Aguirre Sacasa did say Season 5 would have been a big one and there have been hints that a TV crossover would have happened during that round, as well, so that makes the cancellation even more bittersweet.
Meanwhile, Riverdale and Chilling Adventures of Sabrina are sister shows and will be crossing over as had been hoped by certain factions of the fanbase, only via the comics.