Plutonium

So if i were to buy black ops 2 with a key for the microsoft store would it be able to read the files cause i have only seen discusions for steam file,if so would it still be the same install method or would it be different.

so i have looked thru every topic and all the links go back to the same forum witch states u need to have the game files is there a way to get the game files without buying the game and or is there a way just to play and not have any files?