In October 2016, it was announced that a fourth Planet of the Apes film was already being planned.
While promoting Dawn of the Planet of the Apes (2014), Andy Serkis was asked if the AlZ-113 drug had also affected apes outside of Caesar's tribe. Director Matt Reeves and co-writer Mark Bomback took note of this, which led to the introduction of "Bad Ape" in this film.
According to director Matt Reeves, the apes that serve the humans are called "Donkeys," both as a reference to Donkey Kong and, like donkeys, they are used as pack animals.
According to director Matt Reeves, it was Woody Harrelson's idea to begin addressing Caesar by ticking off the military rivals of the past, "Wellington and Napoleon, Grant and Lee, Custer and Sitting Bull," while noting that as an ape Caesar would not know what he was talking about.
The little girl named Nova is named after the character played by Linda Harrison in the first and second films in the original franchise.
According to director Matt Reeves, the name of the group of rebelling humans are the Alpha and Omega, a reference to the bomb the mutants worshiped in Beneath the Planet of the Apes (1970). The logo on their helments and flag matches the original logo on the bomb.
In the first film, Rise of the Planet of the Apes (2011), Caesar could only utter a few words, most notably, "No!" In the second film, Dawn of the Planet of the Apes (2014), his vocabulary had increased greatly and he was able to speak in nearly full sentences with syntax and grammar, but still with a rough tone and cadence to his voice. In this film, he is able to speak nearly identical to what a human can produce, indicating his growth into personhood.
Ape actors Andy Serkis (Caesar) and Terry Notary (Rocket) have also both played King Kong, with Serkis in Peter Jackson's King Kong (2005) and Notary in Kong: Skull Island (2017).
Speaking with MTV, Andy Serkis, was asked about the setting for the upcoming third film and revealed that the third film may not be the conclusion to the franchise. He stated, "It's very, very early in where we choose to drop anchor in the next film. It could be five years after the event, it could be the night after the events of where we left 'Dawn,' so it's very difficult to know where the story is going right at this moment because it's being written as we speak. I know that part of the desire for Matt Reeves to do this next movie is about continuing the enjoyment of seeing these apes evolve. So I don't think we're going to see a situation where we're jumping... It might be three films; it could be four. It could be five. Who knows? But the journey will continue. It might not necessarily be summarized or completely fulfilled in this next one. The point being, eventually we know that we're going to end up back at 'The Planet of the Apes,' but whether it's this film or not, I don't know."
Andy Serkis, Terry Notary, and Karin Konoval are the only actors to be in all three of this Planet of the Apes trilogy. Serkis plays Caesar, the chimp leader of the apes; Notary plays Rocket, a chimp who is one of Caesar's most trusted followers; and Konoval plays Maurice, an orangutan that is another of Caesar's most faithful followers.
Graffiti reading "APE-OCALYPSE NOW" can be seen. This is because the Colonel in this film is reminiscent of Colonel Kurtz in Apocalypse Now (1979).
The giant "X"s that the humans use to tie up the apes outside their camp are the same design as the "X"s used as markers to The Forbidden Zone in the original Planet of the Apes (1968).
The character Nova is an allusion to Nova in the original Planet of the Apes (1968). Both incarnations of Nova are mute, and are given the name Nova by their protectors.
Steve Zahn admitted in a Film4 interview that he cried after seeing the completed film for the first time as he was so moved by it.
Caesar's son shares his name with the Roddy McDowall character, Cornelius, in the original film. Ironically, in the original film series Caesar is the son of Cornelius, eventually naming his own son Cornelius after his father.
Serkis mentioned that the film will be accompanied by a video game, for which he had performed motion capture.
The Colonel (Woody Harrelson) is never addressed by his name, but according to his uniform, it is McCullough.
Before beginning work on the project, Matt Reeves and Mark Bomback decided to get inspiration by watching "a million movies," according to Reeves. Among the films they asked to see at the Fox screening room were: westerns, war movies, Biblical epics, Star Wars: Episode V - The Empire Strikes Back (1980), and all of the previous "Planet of the Apes" films.
Human soldier slogans as seen on the poster include the quote, "The only good ape is a dead ape," which is a reference to the gorilla General Ursus' popular quote from Beneath the Planet of the Apes (1970), albeit the tables have turned.
This is the second movie in the Apes franchise where one of the characters mentions the name of the franchise, in this case being the Colonel as he calls it, "A planet of apes." The first time was in Conquest of the Planet of the Apes (1972) when Caesar, the son of Cornelius and Zira, gives a monologue of the Apes success towards the end of the film.
The Orangutan played by Karin Konoval is named Maurice. In Planet of the Apes (1968), the Orangutan, Dr. Zaius, is played by actor Maurice Evans.
Director Matt Reeves is only the second person to return to direct a Planet of the Apes film (the first being J. Lee Thompson, who directed Conquest of the Planet of the Apes (1972) and Battle for the Planet of the Apes (1973)).
This is the second film that Matt Reeves directed in the rebooted Planet of the Apes franchise, the first being Dawn of the Planet of the Apes (2014).
The yellow beret flash Woody Harrelson's character The Colonel wears is the 1st Special Forces Group (Green Berets), who's home station is Fort Lewis, Washington.
The name of the group Alpha Omega and their motto "We Are the Beginning and the End" refers to the Greek alphabet where the letter Alpha is the first one in the series and the letter Omega is the last one. Furthermore, there is a Greek expression roughly translated as "The alpha and the omega of everything" meaning that if something stands between the beginning (alpha) and the end (omega) then it includes everything.
This is the fifth time Steve Zahn had played a talking animal. Zahn previously played Monty the cat in the Stuart Little films, Archie the bear in Dr Dolittle 2, Sandy Pig in Unstable Fables: 3 Pigs and a baby, and Thunderclap a nyctosaurus in The Good Dinosaur. In this film he plays a chimpanzee named Bad Ape.
The unit insignias seen on the soldiers were from 2nd infantry division and 17th fires brigade both are units at JBLM (joint base Lewis McCord). A truck also had JBLM written on the roof.
Andy Serkis and Woody Harrelson both appear in Star Wars films. Serkis plays Supreme Leader Snoke in the sequel trilogy, and Harrelson plays Beckett in Solo: A Star Wars Story (2018).
As soldiers plan to attack Caesar's wooded base, note 3 different phrases you see on their helmets: 1) "Monkey Killer" 2) "Bedtime For Bonzo" and 3) "The only good ape is a dead one."