One of the surprise hit film franchises in recent years has been the prequel films set prior to Planet of the Apes. The newest film completes a trilogy, but does that mean the end? It seems that the trilogy is the default setting for all blockbuster movie series and so one might expect that War for the Planet of the Apes is designed to end the story, and while director Matt Reeves admits that the new film will complete some storylines, he says it also leaves the franchise open for new ideas in the future. According to Reeves...
One of the things we were really careful to set up, was this notion that Bad Ape was a sign that there were other apes out there and how will Caesar's apes [interact] with future societies that might be elsewhere, that didn't have the benefit of Caesar's leadership?... So we think there's a lot more stories. Yeah.
Nobody was quite sure what to make of the idea to create a prequel to Planet of the Apes, but the first film in the series, Rise of the Planet of the Apes in 2011 was a major hit that has now spawned a pair of sequels. Based on what Matt Reeves tells Screen Rant, it would appear that War for the Planet of the Apes will include the idea that while the particular faction of apes that this trilogy has followed may have chosen to go in one direction, that doesn't mean that there aren't others out there who have evolved quite differently. This would seem to set up the possibility of several potential future films in the series that would change things up either by shifting time or simply geography.
And there is plenty of time. Matt Reeves admits that the world that we will see at the end of War for the Planet of the Apes is not the same world that we know from the beginning of the original film. There's still a lot that will need to transpire to get the world to that point.
One place Matt Reeves doesn't think the movies should go is an actual remake of the original Planet of the Apes. For him, it seems that the space prior to the film is where there are interesting ideas, and it sounds like as long as you view that movie as a canonical part of this current series, there's no reason to touch it.
If War for the Planet of the Apes does well at the box office, and there's every reason to assume that it will, then there's every reason to believe that the studio will be looking for ways to continue the franchise. Odds are it will require new leadership, however, as Matt Reeves will be turning his attention to the DCEU Batman movie very soon.