Just thought I would add that there are a few 'exclusive' in game title backgrounds that you unlock for purchasing the season pass. I can't remember which ones to heart but otherwise all the information provided above is correct. Two DLC packs are out for the Xbox and by purchasing the season pass you'll continue to get the remaining pack for free.
Please note that if you have already purchased DLC prior to the season pass no discount/refund will be returned to you.