A thriller series is usually pretty easy to identifier: blurry cover art, a tagline about some big conspiracy or fight for justice, Kiefer Sutherland running somewhere. But often, the best thriller series look nothing like you think. One of the best thriller series of the decade is something completely different: a medical series that has turned into a pop culture phenomenon that harkens back to TV’s golden age. “improvements” prove to be an issue in The Pitt Season 2. The Pitt Season 2 premieres today at 9 p.m.