Hearts of Iron III: For the Motherland

Summary pulled directly from Steam - Some text may only be applicable to Steam platform

It’s time to dust off the field marshal's baton and take command of any nation in World War II; the largest conflict in history. The first expansion to the critically acclaimed Hearts of Iron III lets you take charge -or delegate -at any level, from division to nation, through a variety of scenarios.
Guide your country to glory from 1936 to 1948 -wage war on the battlefields, in the factories, and at the negotiating table, in the grandest of all World War II strategy games ever made.

Key Features:

War Goals and enforced peace, each member of the faction can demand their own slice and claim it when it is taken
New Partisan system, build Partisan undergrounds to organize your resistance movements and battle not just the occupier but also other ideologies for control of the country
Seize strategic resources to fuel your war machine
New Theatre Interface giving greater strategic information
Improved Internal politics and a new coup system
The return of the battle scenario system to offer new mini campaigns