Previously announced Final Fantasy XIV crossover content in Monster Hunter: World was shown off in full through a new trailer.
While initially we knew the update would include the Behemoth as a new monster to encounter, the trailer also shows off a number of other content additions such as a new version of Kulu-Ya-Ku that wields a piece of a crystal from the Final Fantasy series which has powered it up; Cactuars were also seen as small enemies. The players themselves have their own rewards to claim from these encounters too which appears to be a Dragoon-inspired armor set and Insect Glaive as seen in the trailer. A new Behemoth-themed poogie also seems to be a new reward.
The content will be going live next month on August 1 on both PlayStation 4 and Xbox One versions. For the PC version which launches shortly after that update, we assume they will be saving the update for a later time considering the previous statement that said it would arrive without any of the post-launch content.