In common with the “Breaking Bad” universe are only the barren New Mexico setting and the presence of protagonist Rhea Seehorn, Kim Wexler’s translator in the “Better Call Saul” spin-off. “Pluribus” — titled “PLUR1BUS” — combines acid humor and existential surrealism in a pure sci-fi plot, something seemingly unprecedented for Vince Gilligan. It’s actually a return to his origins: not everyone knows, but the creator began his career as part of the “X-Files” writing team, having written several classic episodes of the series.