On Oct. 2, USCIS issued policy guidance in the USCIS Policy Manual to address inadmissibility based on membership in or affiliation with the Communist Party or any other totalitarian party.
As of yesterday, members of communist parties may not emigrate to the US. Details are here text of the law is here
Communists might wanna go for a variety of reasons (visiting family for example), they just wouldn’t wanna be an immigrant.