The Panzer III was a German Light/Medium tank. It's original role was for tank to tank combat while the Panzer IV dealt with infantry support. The Panzer III was initially equipped with a 37mm gun which was upgraded to a 50mm gun and later an even longer barreled 50mm gun to counter enemy tanks like the T34 and KV-1. Early in the war this was the most numerous tank in the German inventory but it was phased out of service and replaced by the Panzer IV which had a larger turret ring and could take a long barrel 75mm gun. By the end of the war these tanks had no frontline service and served in the training role or had their hull converted to a tank destroyer or assault gun. The last model to be built was Ausf N when the Germans placed the same short barreled 75mm gun from the original Panzer IV on the tank. Side Skirts were put on the tanks from Ausf M onwards.
The Panzer III is the German tier III tank. When fully upgraded this becomes a formidable foe. Against tanks in its tier and lower it can win a one on one but when it gets thrown in the mix with tier IV and V tanks it should be used for support for the heavier team mates. It is very quick so can be used as a dogfighter or as a distarction to tier V tanks since it can outrun their turrets if they fail to turn their hull. The Easy 8 and Cromwell are about the only tanks that can chase you down. The Panzer III can be very effective even in top tier battles if played right just learn how to shoot on the move and you will do well or learn to flank.