Apple has confirmed that the new Apple TV will support Siri for Apple Music sometime early in 2016.
A report by Buzzfeed, including a conformation by Apple, reveals that you'll be able to use Siri to sift through songs and albums when an update for the set-top box rolls out "at the beginning of next year." That means that. in theory, you should be able to say something like "play the new Weezer song" and it should just... happen.
The inclusion on Siri on the Apple TV is one of its biggest new features, but so far it only works for video such as TV shows and movies. Given the addition of Siri is, arguably, long overdue, it's a shame music search wasn't included from the get-go — but it's nice to know that it is at least on its way.