Saturday Night Live. Comedian and former SNL writer John Mulaney makes his hosting debut. If you didn't catch his short-lived sitcom Mulaney — so few did — you should know him as a cocreator of Bill Hader's character Stefon, and the man who used to cause Hader to break up by surprising him with new jokes between dress rehearsal and the live show. Musical guest is Jack White. 11:29 p.m. Saturday, NBC.

Fear the Walking Dead. The prequel/spin-off launches its fourth season right after The Walking Dead's eighth-season finale (note the extended running time), and reportedly features a character from the original. (Honestly, I can no longer bring myself to watch either one, but your mileage may vary.) 10:10 p.m. Sunday, AMC. Moves to 9 p.m. the following week.

Supergirl. Laurie Metcalf is everywhere. Here the Roseanne costar — and Oscar nominee for Lady Bird — guest-stars as the estranged mother of Winn (Jeremy Jordan) who's trying to reconnect with him. Her character happens to share a first name, Mary, with another of her roles, Sheldon Cooper's mother in The Big Bang Theory. 8 p.m. Monday, CW.

I Am Evidence. Law & Order: SVU star Mariska Hargitay produced this documentary about the hundreds of thousands of rape-evidence kits that remain untested, spotlighting four women who set out to trace what happened to theirs. 8 p.m. Monday, HBO.

Civilizations. Liev Schreiber (Ray Donovan) narrates this nine-part PBS coproduction with the BBC that traces art  across the ages. This week's premiere goes back 70,000 years to the earliest known examples of humans expressing themselves artistically. 8 p.m. Tuesday, WHYY12.

Ice Bridge: The Impossible Journey. Could Ice Age people have arrived in North America on an ice bridge over the Atlantic 6,000 years before humans crossed the Bering Strait? This one-hour special explores a theory that grew out of a 2012 archaeological discovery on an island in the Chesapeake Bay. 8 p.m. Wednesday, Smithsonian Channel.

Bill Nye: Science Guy on POV.  The independent documentary series kicks off its 31st season with the national TV debut of this 2017 film about the former children's show host, who took on a new mission to educate adults and to challenge those who've rejected science they don't agree with. 10 p.m. Wednesday, WHYY12.

Scandal. Shonda Rhimes' addictive D.C. drama signs off after seven seasons with an episode directed by Havertown's Tom Verica. 10 p.m. Thursday, ABC.