IMDB’s description:
Armed with only one word, Tenet, and fighting for the survival of the entire world, a Protagonist journeys through a twilight world of international espionage on a mission that will unfold in something beyond real time.
Tenet is a spy thriller, with a scifi / time travel? element intermixed. The movie opens with The Protagonist, played very well by John David Washington, having a mission go bad. After being presumed dead, he is tasked to a secret society to help save the world from an apocalypse. Everyone in this movie assumes ‘nuclear apocalypse’, but we aren’t so lucky.