Call of Duty 4: Modern Warfare is a single-player and multiplayer first-person shooter game.

The campaign follows two parallel storylines set in a contemporary world threatened by international terrorism and civil unrest. Players alternate between two protagonists: Sergeant Paul Jackson, a U.S. Marine deployed in the Middle East, and Sergeant John “Soap” MacTavish, a British S.A.S. operative involved in covert missions across Europe and Russia. Their operations uncover a conspiracy involving ultranationalist forces and rogue military elements that threaten global stability. Across both perspectives, the player experiences high-intensity firefights, stealth infiltrations, and cinematic sequences that frame the unfolding crisis.

The multiplayer component offers competitive online play across numerous modes, including team deathmatch, free-for-all, search and destroy, and domination. Players earn experience points by completing objectives and eliminating opponents, gradually unlocking new weapons, attachments, and perks that customize loadouts. Killstreak rewards, such as calling in UAV reconnaissance, airstrikes, and attack helicopters, add a layer of tactical advantage.