Call of Duty 4 has limited multiplayer when compared to the more recent CODs, but the online servers are still up and running.
It has very limited to no split-screen campaign, but you can play offline split-screen modes, like team death match and domination with up to 4 players on one console.
The more recent Call of Duty's have moved towards a more multiplayer friendly zone, with COD MW3 having not only a split-screen Survival mode and Spec Ops but also allowing you to take a +1 in split-screen online multiplayer.
Advanced Warfare is set for release on November 4th, 2014 and though we can't be sure whether there will be a multiplayer campaign, new features have been put in the online multiplayer, with scorestreaks coming back.