BillionsThe sharp series “Billions” (Showtime, 9 p.m.) begins its fourth season with an odd alliance between  two who had been nemeses for the past three, Damian Lewis’ Bobby Axelrod and Paul Giamati’s Chuck Rhoades.

A new series on the rise and fall of Richard Nixon seems to take a negative look, judging from the title, “Tricky Dick” (CNN, 9 p.m.). Then again, the 3yth president was the first to leave office amid a growing scandal.

Friends come visit on the season finale of the fine, fine “High Maintenance” (HBO, 10:30 p.m.).

Donnie Wahlberg hosts a new series about serial killers and such on “Very Scary People” (HLN, 9 p.m.).

“Luke Perry: In His Own Words” (Reelz, 9 p.m.) remembers the actor who died this month at 52, following a heart attack.

Kensi and Deeks are finally wed on “NCIS: Los Angeles” (CBS, 9 p.m.).

Mr. Wednesday prepares a battle on “American Gods” (Starz, 8 p.m.).

On “Now Apocalypse” (Starz, 9 p.m.), Ulysses looks into the alien reptile conspiracies.

Among the surprises in “The Case Against Adnan Syed” (HBO, 9 p.m.) is finding out what happened to Don.

Auditions continue on “American Idol” (ABC, 8 p.m.); duels begin on “World of Dance” (NBC, 8 p.m.).

A detours’ prison in Missouri gets the four of “Finding Justice” (BET, 8 p.m.).

Miles gets an offer to join a podcast network on “God Friended Me” (CBS, 8 p.m.).

Lex Luthor gets a furlough on “Supergirl” (CW, 8 p.m.).

An outsider arrives to rehash the past on “The Walking Dead” (AMC, 9 p.m.). Then they rehash the episode on “The Talking Dead” (AMC, 10:07 p.m.).

Trump’s problems are showcased on “The Circus: Inside the Wildest Political Show on Earth” (Showtime, 8 p.m.) and, probably, on “Last Week Tonight with Jon Oliver” (HBO, 11 p.m.).

Eva gets married on “The Real Housewives of Atlanta” (Bravo, 8 p.m.).

On “The Simpsons” (Fox, 8 p.m.), Bart develops his video game skills.

Gene wants to save a blob on “Bob’s Burgers” (Fox, 8:30 p.m.).

A hidden room is explored on “Charmed” (CW, 9 p.m.).

There’s a bachelor party for Rafi on “SMILF” (Showtime, 10:30 p.m.).

“Married to Medicine Los Angeles” (Bravo, 9 p.m.) has something called a Dollhouse Brunch.

The fake match between women is finally on for “Total Bellas” (E!, 9 p.m.).

“Black Monday” (Showtime, 10 p.m.) looks into Mo’s past.

Tensions mount between “Good Girls” (NBC, 10 p.m.).

“Madam Secretary” (CBS, 10 p.m.) tries to help a Pacific island before a typhoon hits.

Turner Classic Movies’ Sunday night salute to Irish movies finds its most appropriate day with “The Quiet Man” (8 p.m.), “The Raising of the Moon” (10:30 p.m.) and the silent “The Bride’s Play” (midnight). Then comes two films by Keisuke Kinoshita, “Farewell to Dream” (2 a.m.) and “The Garden of Women” (3:30 p.m.).

NBA action includes Philadelphia at Milwaukee (ABC, 3:30 p.m.) and Minnesota at Houston (ESPN, 9 p.m.).

Hockey has St. Louis at Buffalo (NHL, 5 p.m.), Philadelphia at Pittsburgh (NBC Sports, 7:30 p.m.) and Edmonton at Vegas (NBC Sports, 10 p.m.).

Spring baseball includes Minnesota vs. Toronto (MLB, 1 p.m.).

In men’s college basketball’s championship Sunday, it’s Harvard at Yale (ESPN2, noon) in the Ivy League final; Tennessee vs. Auburn (ESPN, 1 p.m.) in the SEC final, Saint Louis vs. St. Bonaventure (CBS, 1 p.m.) in the Atlantic 10 final, Georgia State vs. Texas Arlington (ESPN2, 2 p.m.) in the Sun Belt final, Houston vs. Cincinnati (ESPN, 3:15 p.m.) in the American Athletic final, and Michigan vs. Michigan State (CBS, 3:30 p.m.) in the Big Ten final.

Then comes the big NCAA tournament selection show (CBS, 6 p.m.).

Women’s finals have American at Bucknell (CBS Sports, noon) in the Patriot League, Abilene Christian vs. Texas A&M (CBS Sports, 2 p.m.) in the Southland, Saint Francis at Robert Morris (ESPNU, 2 p.m.) in the Northeast, and Princeton vs. Pennsylvania (ESPNU, 4 p.m.) in the Ivy League.

The final round is played in golf’s Players Championship (NBC 1 p.m.).

NASCAR runs its Auto Club 400 (Fox, 3:30 p.m.).

Alliance of American Football games include San Antonio at Atlanta (CBS Sports, 4 p.m.) and Birmingham at San Diego (NFL, 8 p.m.).

Sunday Talk

ABC: Sen. Chris Coons. CBS: Sn. Tim Kaine. NBC: Sens. Amy Klobuchar and Pat Toomey. CNN: Klobuchar, Reps. Rashida Tlaib and Jim Banks. Fox News: Acting White House Chief of Staff Mick Mulvaney, South Bend Mayor Pete Buttigieg.