The feature is still in development but features tentatively planned include the ability to create custom maps and game modes. Unranked Dedicated Server Files will be included with all the necessary tools so you can run servers with custom content and an Unranked Server Browser will allow players to search for said servers.
These features won’t be available at launch, with a closed alpha planned for March 2016 and an open beta planned afterward.
These are the features I think need to be in Call of Duty games going forward, if they want to keep their community strong. However, seeing how these features won’t be available to the public until six months after the game’s release at the earliest, this feels like an afterthought that will be a little too late once it’s finally released. Maybe Infinity Ward can include this right out of the gate for the next Call of Duty.