S. 108 aims to make members of the Chinese Communist Party and their family members ineligible for certain types of U.S. visas, specifically F or J visas. An exception is made if denying entry would conflict with international agreements related to the United Nations...
Simple Explanation
The bill is about making rules so that people who are part of the Chinese Communist Party, or their relatives, can't get certain visas to visit or study in the U.S., but there are exceptions if it would cause problems with agreements or if the President thinks it's important for keeping the country safe.