Poland has been in an unfortunate geographical position between Germany and Russia so that when the Germans fight the Russians, Poland always gets pounded. Poland is like the boxing ring of Eastern Europe.
Interesting enough, in 1934, when Hitler first achieved power, he saw Poland as a potential ally, with one of his heroes, Marshall Pilsudski, who he greatly admired for his victory over The Red Army in 1920.
Hitler even attended a memorial service for Pilsudski, and when the Nazis invaded Krakow, he ordered an honor guard at Pilsudski’s grave.