The Department of State has published the names of individuals who are now on the Department of Treasury's Specially Designated Nationals and Blocked Persons List due to harmful activities linked to the Russian government. As a result, these individuals' U.S. properties are blocked, and U.S. citizens are generally not allowed to conduct transactions with them. The information, along with the list, can be accessed on the Office of Foreign Asset Control's website.
Simple Explanation
The U.S. Department of State has put certain people on a list because they did bad things connected to the Russian government, and now their U.S. things are not allowed to be used or traded with.