Question: Frequent John Woo collaborator and actor Chow Yun-fat joined the cast of which crime thriller to make the sequel in 2016?
Context: The Story of Woo Viet is a 1981 Hong Kong political drama directed by Ann Hui and starring Chow Yun-fat as the title character, Woo Viet.  The assistant director was Stanley Kwan and the action choreographer was Ching Siu-tung. Once a Thief () is a 1991 Hong Kong caper film written and directed by John Woo, starring Chow Yun-fat, Leslie Cheung, Cherie Chung, Kenneth Tsang, and Paul Chu.  The film was released in the Hong Kong on 2 February 1991. A Better Tomorrow 2 is a 1987 Hong Kong action film written and directed by John Woo.  A follow-up to its popular predecessor, "A Better Tomorrow", the film stars returning cast members Chow Yun-fat, Ti Lung and Leslie Cheung alongside new cast member Dean Shek.  The film was released in Hong Kong on 17 December 1987. Chow Yun-fat, SBS (born 18 May 1955), previously known as Donald Chow, is a Hong Kong actor.  He is best known in Asia for his collaborations with filmmaker John Woo in the heroic bloodshed-genre films "A Better Tomorrow", "The Killer" and "Hard Boiled"; and in the West for his roles as Li Mu-bai in "Crouching Tiger, Hidden Dragon" and Sao Feng in "".  He mainly plays in dramatic films and has won three Hong Kong Film Awards for Best Actor and two Golden Horse Awards for Best Actor in Taiwan. Johnny Woo, real name Liu Chan Yeun, is a fictional character appearing in "2000 AD" and then in "Judge Dredd Megazine".  Created by Gordon Rennie and PJ Holden, he is a thinly veiled stereotype of the action hero popularised by director John Woo, after whom he is named, and is based in the fictional city of Hong Tong (the 22nd century version of Hong Kong).  His visual appearance is based on the actor Chow Yun-fat. Cold War 2 is a 2016 Hong Kong-Chinese crime thriller film written and directed by Longman Leung and Sunny Luk.  The film is a sequel to the 2012 box office hit, "Cold War", and stars returning cast members Aaron Kwok, Tony Leung, Charlie Young, Eddie Peng, Aarif Rahman, Ma Yili and Alex Tsui, joined by new cast members Chow Yun-fat, Janice Man, Tony Yang and Bibi Zhou.  "Cold War 2" was released on 8 July 2016 in 2D, 3D and IMAX 3D. The Killer () is a 1989 Hong Kong action film written and directed by John Woo, and starring Chow Yun-fat, Danny Lee and Sally Yeh.  Chow plays the assassin Ah Jong, who accidentally damages the eyes of the singer Jennie (Sally Yeh) during a shootout.  He later discovers that if Jennie does not undergo an expensive operation she will go blind.  To get the money for Jennie, Ah Jong decides to perform one last hit. A Better Tomorrow () is a 1986 Hong Kong crime film directed by John Woo and starring Ti Lung, Leslie Cheung and Chow Yun-fat.  The film had a profound influence on the Hong Kong film-making industry, and later on an international scale. Hard Boiled () is a 1992 Hong Kong action film written and directed by John Woo, and starring Chow Yun-fat as Inspector "Tequila" Yuen, Tony Leung Chiu-Wai as Alan an undercover cop, and Anthony Wong as Johnny Wong, a leader of the criminal triads.  The film features Tequila, whose partner (Bowie Lam) is killed in a tea house gunfight with a small army of gangsters.  One of the mob's high-ranking assassins is the undercover cop Alan, who must team up with Tequila for their common pursuit of taking down Wong's crime syndicate.  The film leads up to a climax in a hospital, where the two must rescue innocent civilians and new born babies from the maternity ward while fighting off dozens of mob hitmen. The Replacement Killers is a 1998 American action film directed by Antoine Fuqua in his feature film directorial debut, and starring Chow Yun-fat, Mira Sorvino, Michael Rooker and Kenneth Tsang.  The film was released in the United States on February 6, 1998.  The storyline was conceived from a screenplay written by Ken Sanzel.  Veteran action director John Woo co-produced and choreographed the action sequences.  The film is set in modern-day Los Angeles and follows an emotionally disillusioned assassin who is forced to settle a violent vendetta for a ruthless crime boss.  The film marks the American acting debut for Chow, as his previous film credits included Hong Kong action cinema only.
Answer: Cold War