In the late 1980s, Stan Lee had considered a film/TV series about Shang-Chi and had in mind Brandon Lee, son of martial arts superstar Bruce Lee, for the role. Shang-Chi was visually based on Bruce Lee so Brandon seemed a fitting choice, but the plan fell through.
(at around 30 mins) One of the lower tier fights in Xialing's fight club had a fight between one of the Widows who appeared in Black Widow (2021) and a fighter enhanced with the extremis treatment from Iron Man 3 (2013).
This is renowned Hong Kong film actor Tony Leung Chiu-wai's first role in an American film and his first English-speaking role, even though he has always spoken it fluently.
Simu Liu, when cast as Shang-Chi, was knowledgeable in taekwondo, gymnastics, and Wing Chun. For his role as the Master of Kung Fu, Liu trained in tai chi, wushu, Muay Thai, pencak silat, Krav Maga, jiu-jitsu, boxing, and street fighting.
Meng'er Zhang met action designer Yung Lee while making the movie. The two started dating and by the time the movie wrapped, they were married. To celebrate, Simu Liu took everyone to Disneyland while Awkwafina took everyone to karaoke.