Germany is simple- just make a POD so that Hitler isn't racist. No holocaust, and no mistreatment of slavs means he would gain significant local support against Stalin crucial for victory in the east. Now he brokers a very unrealistic peace with the soviets (in OTL its all or nothing) and regardless of how poorly Italy does, Germany can use that extra manpower to become impenetrable.
The only way Japan can survive is if the USA doesn't exist, really. Even if they'd won Midway, the USN would have those carriers replaced in no time. Japan was just bleeding themselves to death in the Pacific.
The problem is that a non-racist Hitler isn't really Hitler. Many, if not most, of Hitler's decisions were based on racism. Thus WWII would be far different than IOTL.