There is no subscription version of the game. You can pay monthly to get some extra stuff and you have access to the paid dlcs while subscribed but you still can play the base game either way. I'm assuming this is from the humble monthly in which case it's the base version of the game without any expansion/dlcs still completely playable but missing the Morrowind expansion (20$) and the new Summerset expansion (30$ for preorder atm)