While he may constantly complain about portals, Geralt of Rivia from The Witcher series sure likes to travel with them. He just recently made a grand appearance in Bandai Namco's Soulcalibur 6 as a guest character, and soon he will be doing the same in Capcom's Monster Hunter: World as well!
While the details are few and far between, I can tell you that Geralt will come with unique quests that blend The Witcher 3 and Monster Hunter: World's gameplay styles, brand new voice acting to help tie the two series together, as well as a variety of new equipment and combat moves to mess around with. How extensive these quests will be, I'm afraid I don't know, but smacking around Elder Dragons with Geralt sure sounds like a good time!
If you're up for a bit of a sneak peek at what all of this will look like, allow me to share with you the recently posted teaser trailer. Have a gander, it's short but sweet:
You can expect Geralt to arrive to the PlayStation 4 and Xbox One in early 2019, though no exact release date has been given just yet. The PC version will also get the Geralt update, worry not, but it will come at a slightly later date.
It's pretty much the same situation as Monster Hunter: World's newly announced Iceborn expansion. Though to be fair, I don't expect the wait to be particularly long given how much the development on the PC version has sped up in the past few months.
Once more details become available I'll make sure to let you know, but until I wish you the best of luck on your hunts!