I want to know if I am on Black Ops 2 that I can play with someone on Xbox One if I have Xbox 360.
Call of Duty: Black Ops 2 is on the Xbox One backwards compatibility list. This means that people who have it digitally downloaded to their Xbox One will thus connect to the Xbox 360 servers for online play. This is because the Xbox One essentially runs an Xbox 360 emulator for Xbox 360 games.
So yes, you should be able to play with both Xbox One and 360 players.