Question: Which TV series introduced the star who was paired with Robert De Niro in the film Killing Season ?

Context paragraphs:
Robert De Niro Sr.: Robert Henry De Niro (May 3, 1922 – May 3, 1993), better known as Robert De Niro Sr., was an American abstract expressionist painter and the father of actor Robert De Niro.

Robert De Niro filmography: Robert De Niro's filmography includes the year the film was/will be released, the name of his character, and other related notes.  There is also a list of films he has produced and his appearances in theater plays, TV series and documentaries.  He is sometimes credited as Robert DeNiro and Robert De Nero.  De Niro has appeared in over 100 films throughout his career.

John Mariano: John Mariano (born August 5, 1960 in Astoria, New York) is an American actor who has worked in film, television, animation and nightclubs.  He is known for playing tough guys with a comic edge.  His ability of physical comedy has been compared to Jerry Lewis and Buster Keaton.  Keaton's wife Eleanor was quoted as saying; "He reminded me so much of Buster, it gave me chills".  He got his start in films playing a prissy bank teller in "Tough Guys" with Burt Lancaster and Kirk Douglas.  Working steadily in both film and television, he's best remembered on television for playing Johnny the waiter in "Caroline in the City" with Lea Thompson.  A gifted improviser, sketch player and voice-over artist, his impression of Robert De Niro in a sketch entitled "De Niro Sings the Supremes" at The Groundlings, led to him playing a pigeon named Bobby in the cartoon series "Animaniacs", who is based on a character played by De Niro in "Goodfellas".

Righteous Kill: Righteous Kill is a 2008 American crime thriller film with elements of a buddy cop film directed by Jon Avnet, and starring Al Pacino and Robert De Niro.  This is the second film (the first one is "Heat") in which De Niro and Pacino appear together in the same scenes (both De Niro and Pacino starred in "The Godfather Part II", but did not appear in any of the same scenes).  "Righteous Kill" also features John Leguizamo, Carla Gugino, Donnie Wahlberg, Brian Dennehy, and Curtis "50 Cent" Jackson.  The film was released in the United States on September 12, 2008.

Killing Season (film): Killing Season (previously titled Shrapnel) is a 2013 American action thriller film written by Evan Daugherty and directed by Mark Steven Johnson for Millennium Films, as the first on-screen pairing of actors John Travolta and Robert De Niro.  The film pertains to a personal fight between an American and a Serb war veteran.

TriBeCa Productions: Tribeca Productions, a film and television production company, was co-founded in 1989 by actor Robert De Niro and producer Jane Rosenthal in the lower Manhattan neighborhood of TriBeCa.  In 2003, Robert De Niro, Jane Rosenthal, and Craig Hatkoff moved Tribeca Productions to become a part of Tribeca Enterprises, which organizes the Tribeca Film Festival, Tribeca Film Festival International, Tribeca Cinemas, and Tribeca Film.  De Niro, Rosenthal, and Craig Hatkoff are also the co-founders of the Tribeca Film Festival.

Elizabeth Olin: Elizabeth Olin (born December 21) is an American actress.  Her most notable film to date is "God of Love", written, directed, and starring NYU Graduate student Luke Matheny, which won the Academy Award for Best Live Action Short Film in 2011.  She has also appeared in "When in Rome", a Touchstone Pictures film directed by Mark Steven Johnson.  Olin currently filmed "Killing Season" alongside Robert De Niro, John Travolta, and Milo Ventimiglia, which was released in summer 2013.

Showtime (film): Showtime is a 2002 American buddy cop action comedy film directed by Tom Dey.  The film stars Robert De Niro and Eddie Murphy in the lead roles alongside Rene Russo, William Shatner, Pedro Damian and De Niro's real life adopted daughter Drena De Niro.  The film was released in the United States on March 15, 2002.

Heat (1995 film): Heat is a 1995 American crime film written, produced and directed by Michael Mann, and starring Robert De Niro, Al Pacino, and Val Kilmer.  De Niro plays Neil McCauley, a professional thief, while Pacino plays Lt. Vincent Hanna, a LAPD robbery-homicide detective tracking down McCauley's crew.  The story is based on the former Chicago police officer Chuck Adamson's pursuit during the 1960s of a criminal named McCauley, after whom De Niro's character is named.  Heat is a remake by Mann of a TV series he had worked on, the pilot of which was released as a TV movie, "L.A. Takedown" in 1989.

John Travolta: John Joseph Travolta (born February 18, 1954) is an American actor, producer, dancer, and singer.  Travolta first became known in the 1970s, after appearing on the television series "Welcome Back, Kotter" (1975–1979) and starring in the box office successes "Saturday Night Fever" (1977) and "Grease" (1978).  His acting career declined through the 1980s, but enjoyed a resurgence in the 1990s with his role in "Pulp Fiction" (1994), and he has since starred in films such as "Face/Off" (1997), "Swordfish" (2001), "Wild Hogs", and "Hairspray" (both 2007).

Supporting paragraphs: Killing Season (film) John Travolta
Answer: Welcome Back, Kotter