During a car chase scene, there is a brief shot of a "Judge Jessie" bench by a curb. This is a reference to one of their sketches from "Key & Peele" in which Keegan-Michael Key played a daytime-TV Judge named Judge Jessie.
This movie advertised several old Warner Bros. films. The list is as follows. New Jack City, The Matrix, Se7en, Beetlejuice, Mad Max: Fury Road, Point Break (2015), The Shining, Boogie Nights, and Pee Wee's Big Adventure. They also advertised Nightmare on Elm Street. Keanu was a joint production between New Line Cinema and WB. New Line Cinema used to be the house that Freddy built, before it was sold by Bob Shaye.
There is a scene where they're discussing the enjoyment of Liam Neeson after leaving the theater. This is a nod to a skit from their show where Key and Peele are valet parkers praising the acting of "Liam Neesons".
After the scene when they come out of the theatre, they end up listening to a song by N.W.A. Jason Mitchell, who plays Bud in this movie, also portrayed Eazy-E in N.W.A biopic Straight Outta Compton (2015).
After being shot through the hand, Keegan Michael-Key's character, Clarence, then wraps the wound with duct tape. This is an obvious nod to Quentin Taratino's character, Richard, who does the same in "From Dusk Till Dawn" (1996).
There is a Cloud Atlas movie poster on the wall. It was directed by the Wachowskis. They also directed The Matrix which starred Keanu Reeves who voices the cat and is the inspiration for the name and title.