Split-screen co-op exists in Halo: Campaign Evolved on PC, but Halo Studios has hidden it from the menus.

Campaign Evolved" now have a way to access a feature that appears to be unavailable in the game's standard PC version. While ...

With a bit of work, you can enable split-screen co-op for Halo: Campaign Evolved on PC.

Campaign Evolved in split-screen. After all, it’s always great to play with someone sitting next to you on the couch.