What does a lighting artist do?

Well, a lighting artist, it's fairly self-explanatory. It's in the title, but it's basically taking the environment that gets made by the environment artists and level designers and adding lighting to it in a way that represents the art director's visual target for the game, while also keeping in mind things like performance constraints, technical restraints, and also some gameplay considerations like leading the player, making sure that they have good visibility where we want them to have good visibility, that they know where they need to go if it's something like a linear level design.