Will immigration help American companies working in China?

This depends entirely on the company. Some companies only do business in China and don't need you to go abroad, so there is no need, and the company is not willing to apply for immigration or green card for you. But if the enterprise pays more attention to you and sends you to overseas headquarters for further study, and wants you to stay in the company for a long time, and you have a good relationship with your boss, they should help you immigrate, at least get you a green card. As far as I know, Nordic companies, especially Swedish companies, have greater opportunities.