Bots

Bots (known as a short term for robots) are AI-controlled players that appear in Call of Duty: Black Ops, Call of Duty: Black Ops II, Call of Duty: Ghosts and Call of Duty: Advanced Warfare. Bots appear in offline multiplayer or combat training online as well as online local or system link lobby. Bots have four different difficulties (on Ghosts and Advanced Warfare there is five) those difficulties are Recruit, Regular, Hardened and Veteran. Bots are seen only on local or system link lobbies as well as online Combat Training.

Call of Duty: Black Ops
In Call of Duty: Black Ops, Bots first appeared in this game in a combat training lobby. They can be activated by going to the "edit game" options section and changing the number of friendly and hostile bots. In Recruit and Regular difficulty, Bots use weak tactics and never check what's behind them. In Hardened and Veteran mode, bots use all of their tactics and focus and checks who is behind them, and they can usually hear enemies' steps. Bots can use all kind of weapons and equipments. The bots have their clan tag set to [3arc], which is the clan tag used exclusively by Treyarch members. They are programmed and operated by Treyarch.

The player can play the following game modes with bots:
 * Team Deathmatch
 * Hardcore Team Deathmatch (online only)
 * Free for all
 * Hardcore Free for all (online only)

Call of Duty: Black Ops II
In Call of Duty: Black Ops II the bots are back and are more smarter than they were on Black Ops. In Black Ops II bots are smarter and are now able to capture objectives. They not only appear in offline multiplayer, they also appear online on Combat Training on both Boot camp and Objective.

The player can play the following game modes with bots: There are a handful of gamemodes online where the player can play with bots:
 * Team Deathmatch
 * Kill Confirmed
 * Domination
 * Demolition
 * Free for all
 * Capture the Flag
 * Headquarters
 * Hardpoint
 * Bootcamp: A game where teams of mixed humans and bots face each other on Team Deathmatch. Bootcamp is available to players who are below Level 10; once they reach level 10 or higher they can no longer access this game mode.
 * Objective: A game of when any player of any level can play a different gamemode besides team deathmatch, all game modes (expect for search and destory and party games) can be randomly picked to play. Players will earn half XP.
 * Bot Stomp: A game of when a team of six human players fight against six enemy bots. Players do not earn XP for this game mode, But its a good way to practice up and to get to know things better (maps, guns, etc.). On February 4th 2013, Bot stomp was no longer available on the Combat Training Playlists.

Call of Duty: Ghosts
In Call of Duty: Ghosts bots are now much smarter and they will play like a normal human player would in a Call of Duty game, using different tactics similar to actual players. They have the same four difficulties the bots have in Black Ops II but a new one called "Mixed" that randomly picks each Bot a different difficulty. The player can now choose a bot difficulty for each bot team. The bots can also be noted to have a level based on their difficulty, i.e. a Recruit bot will be about level 1 - 10 and a Veteran one will be level 60.

Bots are supported in all game modes.

Call of Duty: Advanced Warfare
Bots also appear in Call of Duty: Advanced Warfare, They are exactly the same skill level as Ghosts bots. They can appear with Supply Drop weapons variants, can use all perks and equipments and scorestreaks. They can also use exo movements. Just like they were in Ghosts, they are supported in all game modes. The "Mixed" difficulty also returns.

Trivia

 * Bots can be kicked due to friendly fire.