Complex sentence: During the war years the cars ferried troops, prisoners of war, horses, freight, and the Jews and others the Nazis considered "undesirables" rounded up in France and sent to concentration camps and likely death in the Holocaust.
Split into simpler sentences: During the war years the Germans used the cars to ferry troops, prisoners of war, horses, and freight. The Nazis also used them to transport Jews and others they considered "undesirables", who had been rounded up in France and then sent to concentration camps and likely death in the Holocaust.