Is immigration a matter of changing nationality? Many people say that they can't come back after emigrating, but don't they have to change their nationality to come back? I'm all confused

There are two identities to immigrate to the United States.

American citizens: you can participate in the American election, but you can't be elected. Can leave the United States for a long time. Only people born in America can be elected as leaders. Holding an American passport, never coming from China, importing overseas Chinese. To enter China, you must register with the police station as a foreigner. Foreigners who have lived in the United States as residents for two years within five years can apply for and pass the exam to become American citizens. It seems that people over 60 can be exempted from the test.

American residents: you can live in the United States for a long time. You can't leave the United States for more than half a year, and the interval between two departures can't be less than half a year, otherwise you will be disqualified. But you can't vote in the American election. You are from China and have a China passport. To go to a country outside the United States, you must obtain a visa at the China Consulate. Other countries, such as Canada, can't go from the United States without a visa from the Consulate General of China. You can become a citizen by passing the exam, but you will never be from China.

Because China does not recognize dual citizenship at present, it will make Chinese people in foreign countries homesick.

However, I hope that in the near future, China will also apply for an overseas Chinese card, which means that it will recognize dual nationality. I think it's good. China people have left their roots, and a lot of savings will return to the motherland.