Combined Arms brings Command & Conquer and Red Alert action mashed together into a single OpenRA powered game and the 1.0 release is out now. Probably one of my favourite standalone OpenRA games, since I grew up playing all the Westwood classic RTS games.
The 1.0 release brings with it chapter VI of single-player campaign so there's now about 30 missions to play, they also added two new 8v8 multiplayer maps, a new music track, a new "Rhino Heavy tank (Stolen Tech - Soviet War Factory)", balanced various units and a few bug fixes.
Combined Arms allows you to play as Allies, Soviets, Nod, GDI and the Scrin. It takes gameplay elements from Tiberian Dawn, Red Alert, Tiberian Sun, Red Alert 2 and even a little Generals. All factions have new units and the game has new artwork and sound effects too. It really is a big merging of the classics together.
Their download includes Linux, macOS and Windows versions. Since it's OpenRA it also has cross-platform online play.
See more and download from their Mod DB page.