"A manned light infantry vehicle with a .50 cal machine gun on top"
The Infantry Assault Vehicle, or IAV, is a killstreak in Call of Duty: Modern Warfare. It is an airdropped armored vehicle that can transport two players, one acting as the driver controlling the IAV's movement and rapid-firing cannon, and another as the gunner operating a pintle-mounted .50 cal machine gun but are exposed to attacks. It takes time for players to enter an IAV, and it can be hijacked by enemies.
The vehicle is automatically spawned in Ground War. This version also features two HEAT rockets that can be fired by the driver/cannon-gunner. The rocket is similar in property to RPG-7 projectiles, dealing powerful damage to enemy armor.