On Twitter Elon Musk responded cryptically to a user asking for Spotify in her car, so it seems like the feature might be coming in the near future.
European Tesla vehicles have a Spotify app, but in North America drivers can only use Slacker Radio. Electrek theorizes that Slacker and Tesla have some kind of exclusivity contract in North America and that it might be coming to an end soon.
Spotify code has been found on North American Teslas before, but the feature has yet to ship out.
— Elon Musk (@elonmusk) July 10, 2019
Since Musk’s Tweet lacks details it doesn’t seem set in stone that the feature is going to arrive here. That said, there’s a strong possibility that it could.