Apple has started rolling out a new feature in Apple Music For You called Friends Mix. As its name suggests, it is a playlist of music that your friends have listened to. Of course, to use this, you have to have friends on Apple Music; this process isn’t simple, and I bet most Apple Music users don’t know that it exists. I assume that if you have no friends, that is you’re not following anyone, then you won’t see this playlist.
The Friends Mix refreshes every Monday.
Update: now, a few hours after I wrote this article, the Friends Mix no longer shows up for me in For You. No idea why.