Will Generation 8 Pokemon appear in 2018 when Pokemon movie 21 will?
I think that either one of two things will happen. One or two new Pokemon will be seen at the end of the sun & moon series, similar to how Blaziken was seen in the Pokemon league against Ash at the end of the johto series. The new Pokemon will not be seen until the new region is introduced in the anime. (Hopefully Ash will be older than 10.) It's possible that some could be introduced in the movie, but I doubt it.