>>1641752
If you're just going for campaign, refer to this video
https://yewtu.be/watch?v=-YmBkZa9KQs
Zombies and Survival/Spec Ops are also great if you're playing single player. You should not play multiplayer at any point, since the games are compromised and you can get your computer bricked by hackers(or your Steam account hijacked if you pay for them for whatever reason).
As for which ones you should play, Black Ops(up to three) are easily the best ones, along with the original Modern Warfare trilogy. If you want more WW2, there is COD 2, COD 3(this one never got a PC release) and COD WaW. Infinite Warfare is surprisingly good, Ghosts has a poopy campaign but instead of zombies it has Extinction(L4D2 esque survival mode, I think you will like it) and I heard good things about MW2019(Rebooted Modern Warfare universe except not really since Zombies confirms that we are dealing with infinite multiverses and characters from Zombies make appearances despite their universe being destroyed and much more that I am not going to go over here) and Cold War, which is technically a direct sequel to Black Ops 1 and a prequel to Black Ops 2 despite the confusing name. Everything else, including WW2, Vanguard and other modern titles are garbage with nothing redeeming about them and should be ignored.
Oh, and the expansion to the original game is pretty good too. If you like PS2 games you also can't go wrong with Finest Hour and The Big Red One. There was also a WaW title unique to PS2 with some cut content from the main release(COD 3 is identical thru out consoles, however).