Call of Duty is a first-person shooter developed by Infinity Ward and published by Activision in 2003. Set during World War II, the single-player campaign follows soldiers of the United States, British, and Soviet armies through a series of tightly scripted missions. The game was built on a modified id Tech 3 engine and became known for its cinematic intensity, massive AI-driven battles, and immersive sound design. Players experience iconic moments like the defense of Stalingrad, bridge assaults, and urban combat. The multiplayer component introduced modes such as Search and Destroy and Behind Enemy Lines, and the killcam feature, showcasing the final moments before death, became a series staple. Call of Duty was a critical and commercial success, launching one of the most influential franchises in gaming history.