UN forces win the Korean war in 1950
To make this happen, I came up with 3 PODs, one major and 2 minor ones. First and foremost, the Chinese civil war drags on for a while longer, and finally ends in mid 1951, with a communist victory. So the CCA is in no position to cross the Yalu in October of 1950, as much as they might want to, because they are still fighting the nationalists.
The war in Korea happens pretty much as in OTL, except for 2 things. When the invasion of Inchon occurs, some of the American forces position themselver to form an 'anvil' to trap the retreating NKPA divisions that are fleeing north from the Pusan perimeter. This was supposed to happen in OTL, but it didn't work. So the NKPA gets caught between the hammer and anvil, and it splinters. Thousands of North Korean soldiers flee east into the Taebak Mountains, where they are mostly reduced to guerilla warfare, and are only a nuisance to MacArthur.
After the liberation of Seoul, the UN troops head north across the DMZ, and capture PYongyang, as they did in OTL. As the city is falling, and the NK govt attempts to flee north, the 173 parachute regt. drops in front of them. With all the luck on their side, the Americans capture most of the high ranking NK govt. personnel, including the great leader, and also manage to free hundreds of American POWs, who were being transported north. Those who don't surrender willingly are shot. Now, the UN forces march north to the Yalu, but halt 50 miles south of the Soviet border. They march right up to the river on the Chinese border, since they have nothing to fear from the Chinese nationalists still in control here.
So the war is over, and the troops come home for Xmas as per MacArthur's promise, and we all live happily ever after. Or do we? How does Stalin respond to all of this? And what does China do when the communists do take control of the country? Can they tolerate the thought of a united, pro-western Korea with Seoul as the capital? Comments, please.