Complex sentence: McCarthyism is rampant and investigators are trying to expose and blacklist Communists in the entertainment industry, and they especially affect Hecky's ability to find work and pressure Sussman to drop him from the show.
Split into simpler sentences: McCarthyism is rampant and investigators are trying to expose and blacklist Communists in the entertainment industry. They affect his ability to find work and pressure Sussman to drop him from the show.