It looks like GOG is giving players a free copy of The Witcher 3: Wild Hunt on PC. There is only one catch; you have to already own the game. In order to take advantage of this great deal, you will need to download the latest version of the GOG Galaxy app. Once you have this downloaded, you have to connect the platform where you purchased the game originally. Unfortunately, the Switch is not included here since there is no Switch integration within the app at this time.
There are a few things to take note of here. You will only be able to renew this offer once, even if you own the game on multiple platforms. Also, if you already own the game on GOG, then you will be able to redeem the game as a giftable code.
You have until June 23rd claim your game. For more information on how to get your hands on The Witcher 3, check out this FAQ from GOG.