The Department of State has implemented sanctions against fourteen individuals under Executive Order 13936 related to Hong Kong normalization. These individuals have been identified as leaders or officials involved in creating or enforcing China's National Security Law in Hong Kong. As a result, their property and interests within U.S. jurisdiction are blocked, and Americans are generally prohibited from doing business with them. The determination was made effective as of December 7, 2020, and they have been added to the Specially Designated and Blocked Persons List.
Simple Explanation
The U.S. government decided that 14 people who helped make a new law in Hong Kong can't have any of their stuff in America or do business with Americans because of what they did. It's like when someone gets grounded for breaking a rule, and they can't play with certain toys or friends anymore.