exist a command to do that?
You mean bots?
No! I'm Spamacus!
17th June 2003
No, he means to spawn the single player NPCs during the game. Yes, this is possible because when you start a level, the computer basically does the same thing a human would do the add an NPC.
However, there is no cheat like in games based on the Quake engine where you would type in "NPC Spawn Stormtrooper". In CoD it would involve knowing the exact pathname to the NPC files and from there I wouldn't know the command to get them to spawn. Ask a modder, they know how to hack bits of code and find out the console commands.