In a recent update to the Switch version of The Witcher 3, CD Projekt Red has baked in the option to transfer saves between the console and a PC. Those who were perhaps reticent about picking up The Witcher 3 for the Switch may have found a little extra motivation to do so today.
Cross-Save in The Witcher 3 works between Steam and GOG.
With update 3.6 to the Nintendo Switch version of the game players can now transfer their save file back-and-forth between either a Steam or GOG copy of the game, making the port a more enticing proposition to PC-bound Witchers. All data is carried over, which means a couple of stipulations are in-place.
Mod-related bugs and blockers can find their way into the Switch version if the PC save was modded, so players are best using an un-modded save. Also, if players have manually altered their save file name on PC then the Switch’s Cloud Save will not be able to recognize and update that save. Outside of those two limitations cross-save will bring over all existing progress, and files can be moved between platforms as required.
Additionally, update 3.6 brings more performance optimizations, a handful of additional graphical options, and touch controls for the UI. For more details The Witcher 3: Wild Hunt Complete Edition patch notes can be found here.