Creed 3 didn't feature Rocky Balboa, which has had viewers asking why isn't Sylvester Stallone in Creed 3. The film continues the story of Adonis Creed (Michael B. Jordan), the son of Apollo Creed, Rocky's friend who was killed by Ivan Drago in Rocky IV. Stallone's famous boxer played a pivotal role in the spinoff franchise, acting as Adonis' coach through Creed and Creed 2. The character, however, didn't return for the series' third installment. His absence was accentuated by the first trailer for Creed 3, which, aside from featuring a brief mention of Rocky, focused solely on Adonis, his family, and his backstory.
https://screenrant.com/why-sylvester-stallone-is-not-in-creed-3/