Complex sentence: Cosby was one of the first black people to appear in the United States as an advertising spokesperson; he is known for his appeal to white consumers in the second half of the 20th century, in an industry seen as slow to accept diversity.
Split into simpler sentences: Cosby was one of the first black people to appear in the United States as an advertising spokesperson. He was known for his appeal to white consumers in the second half of the 20th century, in an industry seen as slow to accept diversity.