Is it possible to build a Call of Duty Style game with a campaign and a multiplayer using UNITY or is it strictly a one or the other type of program because from what I have seen this thing is Badass I like it alot and I would like to put some of my Ideas out into the game world and see what people think of them also if it is a possability then do I need to know advanced coding and things like that or do I just need to know the basic’s because I know the basic’s of coding but I have absolutely no clue what to do with the advanced coding…
Yes you can. Yes Unity is badass. Yes you need to be very skilled at programming to pull this off.
Of course it’s possible, but it’ll take a lot of time. Those games take months for big teams so be prepared that it will take at least a year for you to make a full campaign with the quality of the modern CoD games.
Also it might be difficult to code the AI…
But it’s entirely possible. 
You can but it would be so hard! You also would have to buy a multiplayer connection typing thing. You can find one on the asset store for 85.00$