The correct answer to this open question is the following.
The Resistance Movement and fight in Normandy helped the Allies win the war in that the Allies could contain the march and occupation of the German troops in France. We are talking about "Operation Overload" that landed in Normandy, France on June 6, 1944. Approximately a thousand planes got to Normandy, followed by an impressive navy Allied force of about 5,000 ships and vessels. The Allied forces had used other maneuvers such as "Operation Fortitude" to deceive the enemy, so the German troops had to defend a big portion of the Atlantic coast. This complicated the reaction of the German troops.