Let´s start with a simple question: What purpose do Commander and Leader Units fulfil and how do they influence the rest of your army?

On the left picture you can see a Commander and on the right a Leader Unit, recognizable by their respective icons displaying either 3 little stars for the Commander Unit or a single bigger star for the Leader Unit.





Both Units will show you an Area of Influence which will improve friendly units standing inside its range (Both Commander and Leader Units are exceptions and will NOT be affected by this buff).
The Area of Influence is influenced by the experience of the respective Leader, a vet3 Leader will have a smaller area than a Vet 2. Commanders will always be Vet 2.

Commanders give friendly units in their area 2 additional experience ribbons while Leaders will give only 1 experience ribbon.



It is noteworthy that these buffs can actually promote a unit one level higher than usual which means you can have a unit having 3 experience ribbons displayed under its icon on the map which isn´t normally achievable by adding a manually leveled unit card in your Battlegroup.

You may have noticed the dashed yellow line in the first picture of the previous section that showed you an example of a Leader Unit.
This line shows you another powerful feature of the previously explained unit types which we´ll just call the Radio Network.

When a Leader Unit is in a certain vicinity (1500m) of a Commander Unit it will improve nearby friendly units by 2 experience ribbons instead of the usual 1. It now effectively works just like a Commander Unit.



The end of the dashed yellow line shows you the distance you have to travel until you are in range for the Radio Network to take effect.

When the Radio Network is successfully established this yellow line will be solid and the Commander/Leader Icon will have its colors reversed.



Additionally, if a Leader Unit is in a 1000m radius of a another Leader Unit that is already connected to a Radio Network it will also be connected to it and get all the advantages of it.

This feature allows you to build a Radio Network up to your frontlines without actually risking loosing your Commander Unit.
This goes especially well with Infantry Commanders that can easily hide in the forest.