In real life, one of the lesser-known members of the Ministry of Ungentlemanly Warfare was Sir Christopher Lee. Lee was a step-cousin of Ian Fleming, and Fleming first suggested him for the title role in El satánico Dr. No (1962) while golfing together. The part went to Joseph Wiseman instead, but Lee ended up playing another Bond villain - Francisco Scaramanga in 007 y el hombre con el revólver de oro (1974). Also, Lee famously used his experience in the Ministry operations to educate Sir Peter Jackson, when filming the Lord of the Rings trilogy, on the "sound a man makes when he is stabbed in the back."
Anders Lassen (Alan Ritchson) uses arrows tipped with Bodkin points, which have been in use since medieval times because they are made of hardened steel, and the point is long and steeply tapered enough that with sufficient velocity, the arrow could pierce armor plate and chain mail. They are the ideal arrowheads for a special forces archer.
In the 1968 Kingsley Amis novel Colonel Sun, James Bond says he once spent several months serving aboard a Brixham trawler, suggesting he was a member of the British Small Scale Raiding Force party that conducted Operation Postmaster, the same operation depicted in this film.
Eiza González had to learn how to speak and sing in German. She also had to speak Italian and French.
Henry Cavill on how he came up with his character's signature mustache: "The facial hair was me. That was something which I just thought, "Have some fun with it. World War II, have a crazy mustache, slightly mad characters. Let's really lean into it.""