Elevator

The Elevator appears briefly in Call of Duty 4: Modern Warfare, Call of Duty: Modern Warfare 2, Call of Duty: Modern Warfare: Mobilized, Call of Duty: Modern Warfare 3, and appears as a regularly usable utility in Call of Duty: Black Ops on the multiplayer map Hotel, the campaign mission "U.S.D.D.", and the Zombies map "Five". At least one elevator shaft will appear in the new zombie map Die Rise in the Black Ops 2 DLC map pack, Revolution.

Call of Duty 4: Modern Warfare
In "No Fighting In The War Room," Price, Griggs and Soap ride an elevator to get to the vehicle depot.

Call of Duty: Modern Warfare 2
Elevators are seen in the level "No Russian." Three guards ride up on one, attempting to stop the terrorist attack. The elevator is then blown up by a grenade. If the player kills the guards before they enter the elevator, the player can click the elevator button and use it instead of the escalator, but if Makarov blows it up, the player can use the one right next to it. Taking the elevator is actually longer, because the player has to walk around a big wall to reach the exit. On "Of Their Own Accord," some elevators are seen, with one of them closing and opening on a dead Ranger.

Call of Duty: Modern Warfare: Mobilized
An elevator is used by Sgt. Baker and Captain Weston.

U.S.D.D
In the third mission of Call of Duty: Black Ops, "U.S.D.D.", you play from the perspective of Mason as he is led by the Secretary of Defense Robert McNamara and Jason Hudson to speak to President Kennedy in the Pentagon. At one point on their journey, they turn into a short extension of the room where armed guards stand next to an elevator. After gaining clearance, McNamara and Hudson lead Mason down to the elevator and take him down to the "Nerve Center."

"Five"
The first elevator players are able to use is on the same level as the players spawn, and leads to the second level of the war room. This elevator is very small, with barely enough room for all four players. It is elegant, featuring polished wood walls and a marble ceiling with several plaques that serve only for aesthetics and humor. Because of its small nature, there's only one entrance. The other elevator is located at the bottom of the war room.

Unlike the first, this elevator is much bigger, all four players and dozens of zombies can easily fit in. It resembles a very large cargo elevator. Also unlike the first elevator, this one has two entrances. The first being the main door, and the second being a barrier where zombies can break in. The entrances face different directions at different floor levels.

On both elevators, players can call the elevator if it is not on the same floor as them. Also, players can use this method for free rides if the players are on separate floors which allows players to save money and work together. Camping in elevators is an extremely popular method, as players can hold off in the elevator until things start to get hectic, where a player can take the elevator up or down as short break to allow reloading, reviving of any downed players, or to simply let the suspense of a nerve-wracking close call die down.

Elevators are overall more reliable than teleporters in Five, as they can be camped in, used for short relief, and are more predictable than the teleporters, which take time to memorize the locations they're connected to. But if used foolishly, the elevators can also lock the players in an inescapable corner. Players can also misuse the elevator by using it when other players aren't in it, thus leaving them behind to be killed. Elevators are a lot like the zipline for these reasons, as both can be camped on and used for quick escapes.

The elevator cannot be used during the thief round. Players will get the "Access Denied: Security Protocol 115" message when attempting to use it.

Hotel
Hotel is the first multiplayer map to feature elevators. They take players to the upper or lower levels of the resort, leading either to the inside of the hotel or to useful sniping positions.

Call of Duty: Modern Warfare 3
In "Eye of the Storm," an elevator can be seen closing and opening on a Czech citizen, like in "Of Their Own Accord". In "Down the Rabbit Hole;" Price and Yuri, along with Sandman and Team Metal, use a elevator in the very beginning of the mission. In "Dust to Dust," Captain Price and Yuri use an elevator to get to the top floor to kill Makarov, but it is destroyed by a Little Bird, so Nikolai raises another elevator for Price and Yuri, before the one their standing on falls.

Trivia

 * In "No Russian," if the player kills one of the FSB going to the elevator, but leave the others, the game stops, because Makarov is scripted to kill the guards. The terrorist squad will stop and the FSB will also stop in the elevator. If the player goes all the way down and ride the elevator, the FSB will go through the floor of the elevator.
 * In "No Russian", as well as the special ops mission Terminal, the elevators are made of bulletproof glass.
 * If a player or a horde of zombies stand in the doorway of the elevator, it cannot be used. Displaying the message "Elevator doors blocked" upon use.
 * Also, in the service elevator, if a player is guarding the window, it will say " Elevator doors blocked."
 * If there is a downed player in the elevator on "Five" any other players who try to use the elevator will fail and the player's character will comment that "They cannot afford the ride up/down". (Confirmed on PS3/Xbox 360)
 * Power-ups will float up or down when the elevator is used. This sometimes applies to dead zombies too. This can be rather handy since the gas from any gas zombies will also float away.
 * For some reason all sides of the elevator shaft are properly textured, including the ceiling and floor, even though it is not possible to see them without glitching or cheating.
 * On consoles, if there is a zombie in the elevator when the elevator is moving, the player's aim will forcefully point above or below the zombie. This is a bug with the aim assist.
 * The elevator doors cause damage, and destroy equipment on Hotel.