The Secretary of State has imposed sanctions on four individuals in connection with the enforcement of the National Security Law in Hong Kong. These sanctions, effective from November 9, 2020, are part of Executive Order 13936, related to Hong Kong's autonomy and stability. The individuals, Li Jiangzhou, Edwina Lau, Steve Li Kwai-Wah, and Deng Zhonghua, have been added to the Specially Designated Nationals and Blocked Person List, which means their assets in the U.S. are blocked, and U.S. persons are generally prohibited from dealing with them.
Simple Explanation
The United States stopped doing business with four people because they did things that might hurt Hong Kong's safety and rules. This means those people can't use their money or stuff in the U.S., and Americans aren't allowed to trade or do business with them.