Your timeline is a bit off hzn5pk; the Korean War didn't start until mid-1950, and in 1948 the Chinese Civil War is still undecided.
Crap, your right, sorry about that, I was going off the top of my head. OK so here is three years advances
1950 - N. Korea invades S. Korea
US holds at Puson Perimeter
MacArthur lands at Inchon, N Korea cut off, Race to the Yalu
China (PRC) intervenes
POD - UN declares PRC agressor, allows intervention to force Chinese withdrawl from Korea, allows for unification of Korea under UN.
US begins limited bombing campain of Manchuria after UN approval in December. Limited due to resources in theatre. Naval blockade is also issued.
Truman also decides to increase nuclear bomb development and production. Put it in another gear as a warning to the Soviets. He is adamit though that nuclear weopons will not be used against the Chinese.
1951 - US build up of troops in Europe and Japan, US bombing in China intensifies as more bomber units arive in China. ROC units are allowed to fight PRC in Korea, bolster UN forces. Allied strategy is actually to give some ground to Chinese in Korea to lure Chinese south as forces build up to land in Manchuria.
1951 - US build up of forces in Japan, plan for landing to cut off Chinese.
MacArthur is dismissed by Truman for wanting to use nukes against Chinese.
Bradley is sent to Japan to head invasion of Manchuria in '52. Ike is too important for NATO. Soviets still regarded as main threat.
1952 - Landings in Mancuria succeed as does race to trap Chinese in Korea. Chinese are trapped in Korea and surrender
Truman does not run in election, endorses Adalai Stevenson. Ike resigns and runs as Republican. I like Ike wins the day. Truman leaves office as a more popular president than OTL. Ike is now committed to closing the war down in Korea as he, Bradley and even Truman admit that fighting the Chinese is the wrong war in the wrong place at the wrong time against the wrong opponent.
1953 - Further landings along Chinese coast by US and ROC troops. Ike uses these to bring China to peace table, does not want protracted war against China.
1954 - Peace treaty, Armistice is signed. Korea except for NE portion is under ROK governemnt. Northeast portion for all purposes is made Soviet.
ROC gaines island of Hainan. Most US soldiers exit Asian mainland.
Sino-Soviet rift occurs as PRC wanted more aid from Soviets other than supplies, trainers, and pilots. PRC feels that Soviets abandoned them.
Some US forces remain in Korea for security, but most return home. Military commitment from US is less than OTL. Some US forces are also in ROC.
US more agressive against Cuba, does not let it become Soviet satelite.
Rest of Cold War occurs pretty much OTL. There are more long term effects for PRC China that I probably glossing over. USA still gets bogged down in Vietnam. Although there might be some ripple effect in Eastern Europe with dissenters. But perhaps the Soviet non-responce in Korea is met with more detente', meaning the Soviets are given a free hand to deal with uprisings in Europe. The NATO responce to these brutal show of Soviet force is mere rhetoric.
Japan is a real winner of Korean War as Us dollars flow freely to rebuild Japan to support war effort as US builds up forces.
PATO is formed. Pacific Asia Treaty Organisation, with US, Can, ANZAC, Phil, ROC, Korea, Japan and other developing countries. PATO troops are involved in Vietnam but only slightly larger than OTL, USA is still main contributor. USA still humbled, but experience transforms US military as a result of Vietnam.