There are far too many Warhammer 40K games out there at the moment, most of them forgettable, but even through that fog of bore I'm still a little interested in the upcoming Gladius — Relics of War, the franchise's first attempt at a 4X game.
Developed by Proxy (Pandora) and published by Slitherine (Panzer Corps, Order of Battle), Gladius is set on a single planet where four factions (Space Marines, Astra Militarum, Orks and Necrons) are fighting over...something? Everything? The grim dark future doesn't really need a reason for a war.
As said, it's a 4X game, which means "Explore, Expand, Exploit and Exterminate". Think Civilisation, or Endless Legend, or Master of Orion. It's turn-based, and you research new tech while building outposts, raising armies and doing battle over a hexagonal landscape.
It will be out early next year on PC.