The TV series is nominally based on the 1995 Terry Gilliam film Twelves Monkeys, which was inspired by Chris Marker’s 1962 short film La Jetée.

The series is produced in partnership with Atlas Entertainment, who produced the original feature film, and Charles Roven producer of the original, is one of the executive producers. The TV series script has been reported to have received the tick of approval from the feature film writers David and Janet Peoples.

The TV show uses many of the ideas, concepts and situations that were established in the movie, most prominently the main plot around trying to prevent a plague that would wipe out most of humankind by traveling back in time.

That said, the TV show isn’t a copy or sequel of the movie. Some of the characters are the same or very similar, but only as a starting point. If you’ve seen the film, you will soon realize that the TV show is very much its own take on the movie’s basic storyline.

While the series quickly moves into new territory, it includes numerous subtle nods to the source, including:

• J.D. People’s Mental Hospital is named after screenwriters Janet and David Peoples.
• Jennifer Goines wears the same sweater as Brad Pitt’s film character, Jeffrey Goines, when Cole first meets her in the hospital.
• The Splinter Scientists wear the same iconic glasses as the scientists in the film.
• In Cassandra Complex, Cole wears the same Hawaiian shirt as Bruce Willis’s James Cole at the end of the film.
• The Keys is a destination mentioned both in the film and the series.
• In Memory of Tomorrow, Jennifer is splintered to a WWI battlefield in 1917. This references a scene in the film when Willis’s Cole accidentally travels back to a WWI battlefield.
• The original music theme from the 1995 film also appears is season 2 episode ‘Hyena’ (“Introduccion” From Suite Punta Del Este Arranged By – Paul Buckmaster Written-By – Astor Piazzolla)

Rick Mele from HuffPost TV has a few more insights, which you can read up on in the article he posted, titled ’12 Monkeys’: 10 Things To Know About The Sci-Fi Movie-Turned-TV Show, while Den of Geeks talks in more depth about the 12 Monkeys cross over easter eggs.