Are Chinese Koreans Chinese or Korean? Are they related to Koreans?

The ancestors of the Korean people are Koreans. Because the land here is fertile, they crossed the Yalu River to cultivate it. They are considered immigrants. Those who have survived for generations are of course considered Chinese. Looking at both sides, South Koreans have a similar attitude towards Koreans as they do towards North Korea, a bit like city people looking at rural people. As for nationality, there is no need to take it seriously. It is basically the same as when we talk about Chinese. Sometimes we think of ourselves as Chinese, sometimes as foreigners.