1) “CSI: Vegas” finale, 10 p.m., CBS. Since its debut (shown here) in October, this has focused on a key story: Evidence suggests Hodges faked his lab work. His old friends (Grissom and Sidle) have been trying to show he’s been framed; if they fail, he’ll go to prison and countless convictions will be thrown out. Now – in the 10th and final episode of the season (and maybe the end of the series) – Hodges is missing. His friends desperately search for him.
2) “The Masked Singer” and “Alter Ego,” 8 and 9 p.m., Fox. Last week, “Bull” became the Group A champion, defeating “Skunk” (who, it turns out, was Faith Evans). Now “Banana Split” and “Queen of Hearts” compete for the Group B title, singing alone and with Nicole Scherzinger and Robin Thicke; the winner faces Bull next week. Also tonight, “Alter Ego” has its finale.
3) “Chicago P.D.,” 10 p.m., NBC. Hailey Upton and her boss, Hank Voight, have been overwhelmed by a crisis: They killed a suspect, then buried the body. Now it’s been found and trouble looms; Jay Halstead (Hailey’s lover) demands Voight find a way out. The result is a terrific hour (following a so-so “Chicago Fire” at 9), ending with a couple emotional minutes that will catch viewers by surprise.
4) “It’s Always Sunny in Philadelphia,” 10 and 10:32 p.m., FXX, repeating at 11:03 and 11:35. Last week, this launched its 15th season – a record for situation comedies (other than cartoons). And no, it’s not slowing down; here are two terrific episodes. First, a flashback to a time when the gang didn’t own a bar … and when Dee had a sweet disposition. Then an attempt to replace Dee with (really) a monkey.
5) “Welcome to Earth” debut, Disney+. Here is a steeply ambitious series that goes to the ends of the Earth – literally. The six-parter visits 34 countries on all seven continents, often with host Will Smith joining. In the first hour, he plunges to the bottom of the ocean; in the second, he stands at the edge of a volcano, then descends partway with two experts … one of them blind. Darren Aronofsky (“Black Swan”) produced this with National Geographic, which provided the intriguing experts.