Planet of the Apes 4's title highlights how different the film is
The fourth installment in the rebooted Planet of the Apes series follows the title trend of its predecessors in a way that highlights its differences.

Kingdom of the Apes is the fourth installment in the rebooted Planet of the Apes franchise, and the film's title gives us insight into how it differs from the previous three films. In the series, whether it's a rebooted entry or an original film, the movies follow a specific trend of changing the first few words of each title. The first film in the rebooted series, titled Rise of the Planet of the Apes, chronicled an outbreak of simian flu by Caesar the ape, and the rise of intelligent apes.
The second film, Planet of the Apes, is similar in that the film chronicles the early years of orangutan dominance on Earth, the dawn of their civilization. Finally, War for the Planet of the Apes -- one of Matt Reeves' best films -- speaks for itself again, as Caesar fights U.S. troops over Koba's actions in the second film. Following this trend, Kingdom of the Planet of the Apes sheds light on how the upcoming sequel will differ from its predecessor.
"Kingdom" Could Show An Unused Aspect Of Reeve's Apes Trilogy

usage of the word The "Kingdom" in the title means it can showcase elements that were underused in the first three films. Rising takes place primarily in modern society as it is known in the real world, as it showcases the outbreak of a pandemic. While Dawn and War showcases some elements of Caesar's ape community, they are few, to say the least, because each film has a different focus. In Kingdom of the Apes, though, the fourth film can showcase the ape community in a way its predecessors could not.
The use of "Kingdom" and the timeline of Planet of the Apes 4 are meant to show a full-fledged ape civilization. The movie takes place many years after the events of War for the Planet of the Apes, which could mean that the apes will experience a long period of uninterrupted peace. This could mean the movie follows the surviving members of Caesar's Corporation building a massive civilization around the oasis they found at the end of the previous movie.
How Apes 4’s Title Could Hint At A Different Type Of Conflict

Kingdom of the Apes also hints at the film's central conflict. The use of the word "kingdom" subconsciously makes viewers think of The ancient civilization of the Warring States Period. That could mean the film's main antagonist hails from an alternate ape kingdom, exploiting the potential of smarter apes as the ape flu spreads across the country, as suggested by the bad apes in War for the Planet of the Apes. This would set up a Territory-style massive conflict, rather than the guerrilla action of Dawn's Betrayal conflict and war, while also potentially creating one of the series' best villains.
A new saga begins.“Kingdom of the Planet of the Apes,” picking up many years after “War for the Planet of the Apes,” starts production next month and stars Owen Teague, Freya Allen, and Peter Macon. Directed by Wes Ball, “Kingdom of the Planet of the Apes” arrives in 2024. pic.twitter.com/RqnL4I44pw— Kingdom of the Planet of the Apes (@ApesMovies) September 29, 2022
Apes 4's Title Could Allow For The Franchise's Best Villain

One way of accomplishing this is to introduce apes from different kingdoms as the film's villains. By doing this, Kingdom of the Planet of the Apes can have a very compelling, emotionally resonant villain by making the apes just alternate versions of Caesar. As demonstrated in the first three Apes films, Caesar's struggles make him an incredibly compelling protagonist, and the possible titular kingdom in Apes 4 will feel rewarded for his story. It's possible, however, that another ape community faces a similar struggle with their own Caeser replacements.
This could make for a very compelling villain The head of another of these communities could clash with the apes from the original trilogy. This would combine the best elements of the series' two main villains from Dawn and War respectively. One of the scariest aspects of Koba is that he's an ape when an entire franchise has been built on the mantra "Apes are united and strong." With Colonel War, the third movie is allowed to have a big, explosive conflict at its center. By combining these elements, "Kingdom of the Planet of the Apes" can take advantage of the new title of the upcoming new series while playing the series' best villain.