Answer:
The major outcome of the invasion of Poland in 1939 was that it started World War II.
Step-by-step explanation:
The German invasion of Poland was a military action of Nazi Germany aimed at annexing the Polish territory. The operation began on September 1, 1939 and the last units of the Polish army surrendered on October 6 of that same year. It was the trigger of World War II in Europe and ended with the Second Polish Republic.
The fall of Poland would be accelerated by the subsequent invasion by the Soviet Union on September 17 and the absence of aid from its allies, the United Kingdom and France.