There might be a moratorium on World War 2 shooters, but developers are still allowed to make gun-'em-ups set during the First World War, which has been relatively undocumented in games. Verdun is such a game, concerning itself with "realism", tactical squad management, and "merciless trench warfare". It's been in Early Access for a while—you can read our review of the Early Access version here—but today it has been declared finished, and been released into the wilderness of Steam.
The developers plan to release free themed expansions after this main event, adding Belgian and American troops, a "gritty in-game gore system", and a new, "hardcore" game mode in addition to other stuff. There are a few more details about those expansions in the 'road map' below.