A season pass is a bundle of several DLCs intended to release over a period of time, usually a year, and they usually come with a small discount for buying in bulk or maybe a few extras for buying them all together instead of separately. A battle pass will often have a “free tier” and a “paid tier”, and it’s basically a experience points progression meter that encourages you to keep playing the game longer (and they have an incentive to put the best rewards behind the paid tier to get you to pay for them). Typically battle passes are only available for a limited time, and if you don’t get them while they’re available, you missed out, which creates a greater sense of urgency to play longer during that period of time.