If the U.S. had not gotten involved in the war, and if Hitler had not repeated Napoleon’s folly in invading Russia without finishing off Britain, the Germans might well have won, and the USSR would have had to defeat a strong Germany backed by the resources and manpower of the rest of Europe
And frankly had Hitler treated the Russians in the same manner as the French, a lot of Russians would have welcomed the Nazis as liberators from Stalinist tyranny.