In my standards, one interesting AH scenario i have heard of is Japan's planned invasion of India in WW2, in 1944. The japanese and their allies were making inroads into Assam, the Burma Road had already been abandoned in panic. Fortunately for the Allies, the IJA and the Indian National Army were strategically defeated at the battles of Kohima and Imphal, on the border between modern Burma and India, preventing the Kohima supply and munitions depot from falling into enemy hands, which could possibly result in Japan and the INA vomiting troops into the indian plain.
So, I ask: what if the Axis had decisively defeated the Allies at Kohima and Imphal, captured supplies, and started commiting efforts to an invasion of India?
(My guess is that the eastern Axis would still lose, in some "indian Stalingrad" of sorts. However, i am still curious as to what the effects on post-war arrangements would be if the japanese invade India and achieve at least partial success).