There are two ways to redeem a Steam code, depending on the type of code you have: a gift card code, or a game code.

What platforms does CDKeys sell game codes for? CDKeys sells video game codes for PC (via Steam, GOG, Battle.net, and others), Xbox One, Xbox Series X|S, PlayStation 4, PlayStation 5, and Nintendo ...

As a benefit to previous customers, Ludeon created a Steam code generator so they could officially add the game to their Steam library at no additional charge.