The POD would be a delay of the PRC invasion of Hainan - for whatever reason, the mainland isn't able to attack until the Korean War begins, and after that, the American shield makes it a non-starter.
So now instead of just Taiwan and a few nearby islands, the ROC also has Hainan (and maybe the currently disputed South Seas islands? who, if anybody, occupied them in 1950?). What impact might this have on regional history, and the development of Hainan and the ROC? Would, for instance, Hainan remain the Free Area of Guangdong Province or would it be granted provincial status in its own right?