Szamlek mentioned in an interview with Eurogamer that “Blood and Wine” will be an independent story. Though it will not be closely tied to the main plot, it will still feature Geralt of Rivia as the protagonist. CD Projekt RED had considered using Barengar as the protagonist for the expansion, but Szamlek said nobody liked the idea:

Jakub also mentioned that they had also been thinking about creating a prequel, but this would create complications in writing their plot. The notion was dropped in favor of a better end to Geralt’s story. 

Yes, this expansion will mark the end of Geralt’s role as the main protagonist in The Witcher series. Although Szamlek has mentioned that this is not the end of The Witcher, and nothing is set on stone for the future. Nobody knows how it’ll go, but CD Projekt RED has never been known to let their fans down. 

Szamlek has also acknowledged that there was a fault in Witcher 3: Wild Hunt, as they failed to create a charismatic antagonist. But he assures fans that they are working hard to create the perfect one for the “Blood and Wine” expansion. 

There’s still no official release date for “Blood and Wine”, but it’s set to launch within 2016.

Witcher 3 s Blood and Wine expansion promises a good story and a memorable antagonist   The Witcher 3  Wild Hunt - 28