Despite saying that he was done with the series Sylvester Stallone still seems very invested in the production of Creed II . There hasn't been much movement on the sequel which is said to have star Michael B. Jordan attached but not director Ryan Coogler. Jordan is a very busy guy as he just wrapped production of Black Panther not that long ago and is getting ready to work with Coogler again on Wrong Answer. We don't know anything about Creed II but it seems like Stallone has some ideas.
So he basically wants a Rocky IV type of movie with the the son of Adonis (Jordan) have a fight with either Drago (Dolph Lundgren) or perhaps his son. It has a sort of symmetry to it that we often see in movies. Adonis lost his father to Drago so of course he would want to take the man, or a symbol of the man, in the ring.
There is also the historical precedent. When Rocky IV came out America and Russia were circling each other and waiting for one to make a move. We were in the last six years or so when this movie came out. After so long tensions were high and America was very anti-Soviet Union at the time. For Rocky to beat Drago in a fight wearing American flag shorts was American symbolically punching the Soviet Union out. It would make sense to do something similar now. Putin and global politics have turned Russia into the "bad guy" again in the eyes of the popular culture. If they did something like Adonis beating Drago or his son it would resonate with the modern audience in a similar fashion to the way Rocky IV did in 1985.
There hasn't been much movement on Creed II but it has 2018 listed as its release year. If it's going to happen they need to head into production soon.