What if Germany never invaded France in WWII?
There's no way that would not have happened, Hitler was going to grind France under his boot if all other efforts had to be abandoned to do so. I think in some ways he was actually a bit disappointed that they gave him little opportunity to rain death and destruction on them with their quick surrender; despite hating the French his racist ideology actually overwhelmed that hatred, so when the French surrendered they were treated as well or better than any occupied country - the French ancestors were Celtic tribes from the same branch as the pure Germanic Aryans, and therefore qualified as real human beings in Hitler's world.
However, if Hitler had just gone east after Poland, and attacked the Soviet Union while assuring the rest of the world that he was fighting a war to stamp out global Jewish-led Communism (in Nazi ideology Communism was a Jewish plot, and many other countries associated Communism with the Jewish peoples) and had no designs at all on attacking western Europe, that would have been the nightmare scenario for the whole world.
Stalin did nothing to help the west when his bacon wasn't in the fire, and the west would have done nothing if their bacon hadn't been in that fire also, so the Soviet Union would have been left to fight alone against Germany at a point where they were really, seriously unprepared to defend their Rodina. The particular reason being that Stalin had used the late '30s to execute or imprison almost all of the Red Army's senior commanders, nearly all of the mid-level generals, and tens of thousands of colonels and lower-ranking officers, all for the crime of not being sufficiently loyal to Stalin himself.
In that scenario, a German victory over Russia becomes much more likely. Now with all of the resources and oil he needed, Hitler could have turned west in '41 or ‘42, the western Allies would still have been unprepared and would have been rolled over just like they were in 1940. And if that happened it seems likely that Britain would have little to no option other than to negotiate a peace with Hitler, as the chances of the US and Britain alone retaking Europe with Hitler drawing on the full resources of the continent would have been very, very slim.
Then WWII won't have happened as it means Hitler had to surrender after France and UK declaring war on him after he attacked Poland.
No way to defeat the allies without invading France, no way to survive the allied blocus and strategic bombing either.
Well, then any hope of signing peace with allies would be doomed. Hitler would be forced to keep large army on the western border.
Since French didn't help Poland it is unlikely they would have invaded Germany after the fact - phony war could last a while and turn into cold war.
On the East Soviets may or may not try to invade Germany.
Things would be interesting by 1942/1943.
Situation would be dangerous for Germany with enemies at both gates.
Was Impossible as it was either that or france invaded germany