I had forgotten about this shot from the PAX AUS Art panel:
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I've seen it suggested that the Panzer-IV was added to be used as a Japanese tank (which is a bit silly, since Japan never used the Panzer-IV), but I don't think that argument can be used for our Wehrmacht infantryman here. Germany is coming in some form, and soon... either in the base game, or in one of the early DLC.
Another argument could be that it's "just a generic Northern European infantryman," except that that the only other Northern European civilization in the base game is France, and you're looking at the French modern infantryman in the same image. I suppose it's not impossible that they might add specific units like this just to use for Independent Powers, but it seems extremely unlikely (though that would be darkly funny) that they would make Germany a city-state.