“Old” call of duty is based from WWII, which were made in the early 2000s inspired by Medal of Honor while “New” call of duty is the fictionalized takes within the FPS genre (basically the ones you recognize today). Modern Warfare (the 2007 one) is the title that departed from the WWII genre while World at War tackled at both theaters of WWII (the Pacific and European).
CoD: MW for multiplayer, CoD: WaW for singleplayer
Modern warfare was pretty good but the knife in close was too effective. You could just run through buildings and knife everyone
On second thought that might have been MW2
I don’t remember ever using knife in the og MW