The international posters and US IMAX poster have various variations of the phrase 'The Final Chapter' as the tagline. However Antoine Fuqua in an interview while promoting the film has said a prequel and a sequel could happen if Denzel was still interested.
In the vineyard barrel room in Sicily with all guns trained on him, Robert warns the crime boss that he has 9 seconds to decide his fate. Although it seems far shorter, he actually lets 10 seconds pass before he springs into action.
This movie marks the fifth collaboration between Denzel Washington and director Antoine Fuqua after Training Day (2001), The Equalizer (2014), The Magnificent Seven (2016) and The Equalizer 2 (2018).
The hat worn by "Frank Conroy" in the film says 'Vienna Inn Est. 1960". This hat is from the Vienna Inn bar and restaurant located in Vienna, Virginia, not far from the CIA headquarters in Langley, VA. The Vienna Inn is a local landmark, famous for once being the top seller of Budweiser beer in the nation, and also famous for its chili dogs and wait staff with little patience for anyone.