The tattoo on xXx's leg bears the name "Harry O'Connor". Harry O'Connor was a stuntman featured in xXx (2002), who died during filming. He was the stuntman who doubled for Xander Cage during the famous parachute zip-wire stunt in Prague.
Actress Nina Dobrev, a genuine thrill seeker by her own admission, was so displeased to see that her character in this film was going to be just some "tech geek", that she kept asking Director D.J. Caruso to give her some kind of an action scene until he gave in and added a part where she gets to use a gun. However, because this hadn't been the plan, she became the only cast member in an action scene to not get any sort of gun training beforehand.
This marks the second incident where Vin Diesel opted out of the second entry of a franchise that he originally launched as the lead, before reprising the role again. Diesel also skipped the second entry of The Fast and the Furious franchise, 2 Fast 2 Furious (2003).
Adele Wolff (Ruby Rose) was modelled after Kinessa Johnson. Johnson served in the U.S. Army and did a tour in Afghanistan before becoming an advisor for V.E.T.P.A.W., a non-governmental organization made up of veterans that combats poaching using military tactics.
The fighting style Xiang (Donnie Yen) uses against the N.S.A. soldiers at the end is Wing Chun. Several moves Yen uses include a Lap Sau (block/deflect), Fak Sau (knifehand), Tan Sau (sky palm block), the Wing Chun front kick, and the signature Lin Wan Kuen (a.k.a. chain punch). Donnie Yen portrayed the legendary Wing Chun Grand Master, Ip Man (who was also Bruce Lee's teacher), in Ip Man (2008), Ip Man 2 (2010), Ip Man 3 (2015), and Ip Man 4 (2018).
On the way to recover Pandora's Box in Detroit, Xander's (Vin Diesel's) team is driving a yellow van with the signs "Pork Chop Express" and "since 1985". "The Pork Chop Express" was the name of the truck driven by Jack Burton (Kurt Russell) in Big Trouble in Little China (1986).
During filming, Michael Bisping accepted a UFC title shot, on two weeks notice, to replace injured challenger Chris Weidman. Despite being a huge betting underdog, Michael Bisping defeated his opponent Luke Rockhold in Round 1 by knock-out, to become the UFC Middleweight Champion.
The color-shifting 1967 Pontiac GTO delivered back to Xander Cage (Vin Diesel) by Darius Stone (Ice Cube) at the end of this film is the same SFX "Flame Car" last seen atop the Charles Bridge in Prague, along with Asia Argento and Samuel L. Jackson in xXx (2002). This muscle car has been in a private collection ever since, and still retains most of the original film's Special Effects equipment on-board as constructed for the various practical effect sequences (flame thrower, rocket launcher, ejected hardtop roof, gauges and weaponry, et cetera).
The character of Adele Wolff, played by Ruby Rose, was modeled after Kinessa Johnson. Johnson served in the US armed forces and did a tour in Afghanistan before becoming an advisor for VETPAW, a non-governmental organization made up of veterans that combats poaching using military tactics..
When Gibbons is revealed to be alive at the end, he wears glasses with the left ocular darkened. This is another reference to Samuel L. Jackson's role as Director Nick Fury in the Marvel Cinematic Universe.
When Neymar da Silva Santos, Jr. is introduced during the China Restaurant interview, he is described with "thought to be recruited for The Avengers" which is a reference to Samuel L. Jackson's role as Director Nick Fury in the Marvel Cinematic Universe.
Features several references to the Marvel Cinematic Universe. In the beginning of the movie, The Avengers are mentioned in text. At the end of the movie, it references Nick Fury. It is revealed that Gibbons faked his death and one of the lens of Gibbons' glasses are darkened. Similarly, his character Nick Fury fakes his death in Captain America: The Winter Soldier (2014).