Apple are publicizing their new APIs for Apple Music in iOS 9.3:
Provide controls for Apple Music within your app. iOS 9.3 now supports playback of any song for Apple Music members.
This is a good move, because controlling and managing music is so personal to people. For instance, listeners of classical music (I’m told) don’t necessarily prefer “artist” to be the top level entity, instead preferring the performer. This is an opportunity for 3rd party app developers to get in on the success of Apple’s music streaming service by filling niches that Apple are struggling to cater to with the one-size-fits-all Music app.