These are the Steam peak player count statistics for Call of Duty that I have been tracking for a few years. They are usually updated on a weekly basis on Monday morning but sometimes more often.
If you are unfamiliar with what the Steam peak player count is; it is merely a point in the day (usually 3:00PM ET) when there are the most people in game at that given time – also known as concurrent users.
Interested in some fancy charts to better show the information? Check out the respective Content sections for some highlights.