Creed has been following a similar arc to the Rocky movies from the start, which could mean that some of the framework for Creed IV has already been established. The original Rocky movies began releasing in 1976, when Sylvester Stallone was still a young man. The success of the franchise led to massive expansion with the release of five direct sequels throughout the next three decades, and eventually a spin-off franchise which follows the son of Rocky’s former rival-turned-friend, Apollo Creed (Carl Weathers).

https://screenrant.com/creed-4-predictions-rocky-iv-tropes-expectations/