We now know the first game coming from the collective of (mostly) veteran developers that is Campo Santo, and that game is called Firewatch.
The game's announcement describes Firewatch as "first-person video game where you, as a man named Henry, explore the Wyoming wilderness after taking a summer job as a fire lookout." Obviously, there's much more to the story, and something draws Henry away from his post. His only line of communication is with his boss, Delilah, on the other end of a handheld radio.
Firewatch's being developed on Unity, and is currently planned for a release in 2015 on PC, Mac, and Linux. Console versions are being explored, but the developer couldn't confirm anything just yet.
"Long-term we want the game to be playable by as many people as possible and will aim to be on any platform that fits the design of the game," said the company in its FAQ.