Chasing the Scream: The First and Last Days of the War on Drugs written by
Johann Hari. You can read the excerpt detailing "The Hunting of Billie Holiday" on Politico. It was adapted for the screen by Pulitzer prize-winning playwright Suzan-Lori Parks, so it should come to no surprise that the film has a lot of long, conversational, theatrical scenes.
Besides Day as Holiday, the characters in the film based on real people primarily include the antagonist — Henry Anslinger, played by Garrett Hedlund, the United States' first commissioner of the Federal Bureau of Narcotics, which later became the DEA. In Hari's book, he talks about how Anslinger treated Judy Garland's drug addiction with compassion, calling her “a beautiful, gracious lady,” rather than having her arrested and hounded by cops and federal agents. Holiday was obviously treated much differently.