Stalin just could not stay away from Hitler: after the August 1939 Hitler-Stalin (Molotov-Ribbentrop) Pact ended with war in June 1941, the two sides sent their foreign ministers to a secret meeting in June 1943 to discuss a separate peace, which proved unattainable despite their best efforts because of conflicting territorial claims. The Soviets wanted the status quo ante of 1938, while the Nazis wanted their border on the Dneiper.
This shows the cynical demagogy of Putin's current attempt to portray Russia as the classic anti-Nazi power against allegedly Nazi Ukraine. Stalin in reality had a decided affinity for Hitler!