Death in Baldur's Gate 3 is final—if you're playing Honour Mode, that is. For everyone else, returning to the land of the living is but a revivify scroll away.
This is a streamlining of D&D 5e (the system the game's built upon) and its resurrection mechanics—which typically require powerful magic that grows costlier and more advanced the longer the poor sod in question has been dead.
Originally, though, this process wasn't quite so simple. As Larian co-founder and CEO Sven Vincke told PC Gamer in a recent roundtable podcast, Baldur's Gate's development team once planned an entire mechanic that'd task players with escaping the fugue plane. «Whenever you died, you were supposed to go to the fugue plane,» Vincke explains. "[We] had this entire thing so that when you died, you were gonna go into the fugue plane … for instance, you would be in the fugue plane but the rest of your party would still be walking around in the material plane." Vincke wasn't able to go into the details, especially since the studio would be within their rights to retool any systems they built for it for whatever's coming next, but that won't stop me from rolling up my sleeves and doing some speculation.
The fugue plane in Forgotten Realms lore is described as a neutral area within the Astral Sea—as AD&D Forgotten Realms book «Faiths and Avatars» puts it, it's «the place where spirits go right after people die.» Gods will come and sort the faithful into their respective heavens.
If you didn't sign on for any particular god you, uh, get formed into «a living wall around the City of Strife» and are «left there until [you] dissolve».