They forced the US to retreat from Chosin Resevoire. They paid with over 48000 casualties, possibly as high as 60k, most of them from the sub-zero weather.
It ended any hope of the UN re-uniting the peninsula, but the heavy Chinese casualties meant they couldn’t go on to take South Korea.
In the course of that war they lost 1,000,000 men. A salute to General Matthew Ridgeway. He set up quad 50 caliber machine guns to repel human wave charges. The “meat grinder “ did a great job.