"Due to some music licensing issues, we've had to temporarily remove Vice City PC from digital stores. We'll make it available again as soon as possible," a statement to Game Informer reads. Rockstar hasn't specifically called out which song(s) are at the heart of this dispute, but tells Game Informer this current licensing issue won't affect the upcoming mobile port.
Cinema Blend suggests it's Michael Jackson's "Wanna Be Startin' Something" that's the problem, which Sony Music Entertainment owns. If you've already purchased Vice City through Steam or your other favorite digital distributor, you should run into no problems installing and playing the game – unless you do, in which case you'll want to call your cousin Carl. He's real good with them computers.