The main use an exoskeleton would have is to increase the load someone can carry. The best use would be to outfit 1 soldier in a squad with it so they can carry heavy weapons, like a .50 cal MG or automatic grenade launcher. But in most cases it's better in almost every way to use a small (or large and armored) vehicle to accomplish the same. It wouldn't be special forces necessarily, it would be for mountain, jungle, or urban operations. Power requirements & reliability would make it tricky for a long time, and being dedicated for tricky environments like that would only make it harder.