Sam Giancana was a Sicilian American mob boss.
In the Timeless Universe
On September 21, 1962, Giancana was watching the Rat Pack, including Frank Sinatra, Sammy Davis Jr., and Dean Martin, perform at the Sands Hotel and Casino in Las Vegas. While Lucy Preston, Rufus Carlin, and Wyatt Logan were scanning through the audience disguised as waiters in search of Garcia Flynn, Lucy points out Giancana to Wyatt. She calls Giancana the biggest mobster in the country and tells Wyatt that he worked with both the Central Intelligence Agency and John F. Kennedy to attempt to assassinate Cuban leader Fidel Castro. Wyatt then tells Lucy to focus on their mission to find Flynn.
Sam Giancana at Wikipedia