Kirk McElhearn:

Ratings are totally absent from the iOS 10 Music app, with no option to turn them on. Currently, on iOS 9, you can view a rating or rate a track by tapping its album artwork while it’s playing, but only for tracks in your library; you can’t apply star ratings to Apple Music tracks.

I’ve noticed this too, but haven’t said anything yet. Please Apple, don’t get rid of star ratings. I use them a lot in my music lists and for auto-playlists for music that I’ve highly rated over time. I’m hoping they just haven’t turned it on the iOS beta, but will in a future update. I’ve been rating music since iTunes first came out—losing all of that now would be a shame.