re: cs skins and stuff

 I'm a big CS GO fan, but the whole CS GO skin industry always felt pretty far away from me. I've always had skins, and most of them just dropped for free from playing the game. I only found out fairly recently that there are separate platforms with their own CSGOroll Promo Codes where you can play more, win stuff, and use your CS GO skins. So is this basically an industry within an industry? Or is it actually something completely separate that's just tied to CS GO?