The Call of Duty Series is a popular franchise of first-person shooter video games, developed by various studios under the umbrella of Activision. The series began in 2003, focusing initially on World War II settings, but has since expanded to include modern warfare, futuristic battles, and even historical conflicts. Each game typically features a single-player campaign, multiplayer modes, and cooperative gameplay. Over the years, the series has introduced iconic titles like Call of Duty: Modern Warfare and Call of Duty: Black Ops, which have garnered critical acclaim and a massive player base. The franchise is known for its engaging storytelling, realistic graphics, and competitive online play, making it a staple in the gaming community.