https://www.gamespot.com/articles/ps4s-monster-hunter-world-horizon-gear-available-r/1100-6456339/

Monster Hunter World has released for PS4 and Xbox One, but PS4 players have some additional content right from the outset. On the official Capcom Unity blog, the publisher confirmed that the first quest to get the PS4-exclusive Horizon Zero Dawn armor would be available right at launch, but it won't be around for very long.

Right now, PS4 players are able to embark on the first part of the Horizon Zero Dawn Event Quest. You'll need to attain a Hunter Rank of 6 or higher in order to accept the quest, which has you hunting eight Barnos. After completing the mission, you'll obtain materials that can be forged into Horizon-themed Watcher armor for your Palico companion.