Mortal Kombat X has been getting skin packs since release, along with Kombat pack 1 which includes 4 new fighters. Kombat pack 2 can be bought separately from Mortal Kombat XL but in order to get the skins, you will have to pre-order XL.
Mortal Kombat XL will be a re-launch of Mortal Kombat X and it will hit stores in March. Along with the original game, XL will include all DLC. This includes the newest character pack along with every costume and skin that has been released as part of the season pass. The extra large version of the fighting game is now available to pre-order for PS4, Xbox One and PC, and will cost $60.