BlacKkKlansman by Spike Lee (and others)
This film is based on the book Black Klansman by Ron Stallworth. In it, a young black cop decides to infiltrate and expose the Klu Klux Klan in Colerado.
I love the trailer for this, particularly the bit where Ron Stallworth phones the local Klan headquarters explaining why he wants to join them.
Can't wait until it's out in cinemas in the UK. (24th August 2018).