Call of Duty: Modern Warfare (MW) and its sequels Modern Warfare 2 (MW2) and Modern Warfare 3 (MW3) are FPS video games primarily developed by California-based developer Infinity Ward and published by Activision. They are the fourth, sixth and eighth installments of the Call of Duty franchise. The MW story arc marked a significant departure from the initial Call of Duty series roots, in that it moves the setting of the game to the present-day/near-future from the previous iterations that were set in World War II. This shift allowed the developers to tap into the geopolitics post-9/11. In the single-player campaign, the player takes on the roles of various characters, including a United States Marine and a British Special Air Service (SAS) operative. The player's perspective changes dependent on the character and as the plot evolves through non-playable events and playable missions. Missions typically include objectives based around eliminating enemies, passing checkpoints, securing objectives against attackers or destroying an enemy location. In the multiplayer version, the series utilizes these mechanics for various team-based and deathmatch-based modes across various maps. The multiplayer modes established several features that became the de-facto benchmark for similar games in the genre in that players earn experience points, allowing them to advance in level, unlock new weapons, and open up further customization options, challenges, and gameplay modes. The series also popularized the notion of rewarding players for “Kill Streaks.”