The new Power of Shadow DLC is on Xbox One right now and 'soon' for PS4 and PC. With it you get a new skin based on the Black Hand (the bad guy up there who kills Talion's family at the start of the game) and, more interestingly, there's a new set of runes that could shake the game up a bit.
The 'One with Nature' rune boosts immunity to poison, both from Uruks or Ghuls. 'Ascendant' doubles your available Focus Time, enabling you to pull off slow-mo archery for longer and, finally, the Elven Grace rune raises defence so that you take less damage. Considering how tough the game can be when you get mobbed, that last one sounds really, really useful.