The answer is simple: Call of Duty: Modern Warfare. The game originally launched back in 2007, the brainchild of both Infinity Ward and Activision. It  was the fourth main entry in the Call of Duty series, and it took the story setting away from World War II for a more modern approach. Because of this, there's a much different, more austere tone that players really gravitated to, much like the new Modern Warfare that released just last year in 2019. 

Call of Duty 4: Modern Warfare followed the British Special Air Service (SAS) recruit Sgt. John "Soap" MacTavish for most of the game, and it introduced a series of NPCs players are now quite familiar with — Captain Price, Gas, Vasquez, Griggs, and Nikolai. 

The game follows a war that breaks out in Russia and a series of operations that take place during the scuffle. It's a gritty, action-packed adventure that'll grab your attention far beyond the bounds of its campaign.