Yes, Black Ops 3 and Just Cause 3 are both Full Controller Supported. So you can just plug in your PS4 Controller and play. For other games, that are not Full Controller Supported (i.e Skyrim) you'd need a third party software like InputMappter or DS4Windows for it to work. You can check the Steam Pages of Steam Games to see if they are full Controller supported. Just to add, If you don't have Windows 10, you might need InputMapper of DS4 Windows anyway, but I'm not certain.