At The Game Awards, we got a look at the announcement trailer for Campo Santo's next game, called In The Valley of Gods. Due in 2019, the game is unrelated to Firewatch, though "if you enjoy well-told and well-acted dynamic video game stories, or you just really liked Firewatch, this game is for you."
"In the Valley of Gods is a single-player first person video game set in Egypt in the 1920s," reads the official site's FAQ. You play as an explorer and filmmaker who, along with your old partner, has traveled to the middle of the desert in the hopes of making a seemingly-impossible discovery and an incredible film."
Check out the trailer above, and there's a Steam page for it as well.