Canadian immigrants immigrated to China.

China's nationality law does not recognize dual nationality. Therefore, when you immigrate to Canada and have Canadian citizenship, your China citizenship will naturally disappear, and so will immigration to the United States.

Citizenship of Canadian immigrants:

On the issue of nationality, each country has different regulations, and Canada's current Citizenship Act recognizes dual nationality. According to the current law, Canadians who have obtained citizenship of other countries can still retain their Canadian citizenship unless they apply for renouncing their Canadian citizenship and get the approval of a citizen judge. China also does not allow citizens of other countries to have our nationality at the same time. You can only choose between China and other nationalities.