This case is from the Ninth Circuit, which includes Hollywood, and affects creative works about historical figures.
https://www.hollywoodreporter.com/thr-esq/in-jersey-boys-ruling-appeals-court-adopts-new-standard-for-nonfictionBasically, if you claim it's a true story, anyone else can later build a biopic based on those facts. There's no allowance for how difficult the research was, or if the story was even published. In other words, the "hot news" concept of copyright doesn't extend to biographies.
My mind immediately went to the common practice of simplifying a biography by using composite characters. The composite seems to be protected by copyright, but not the underlying facts used to build it. If you combined nine bit players into three minor characters, someone else could shuffle the same nine so long as they don't steal a specific line you created.
Stuff that you made up from whole cloth to embellish the story? Completely protected
unless you wove it as part of a true story without calling out the fake bits. The main character's imaginary drug trip is still your own, but anything believable falls into the public domain. (The libel aspect of such a fabrication is a whole other topic.)
Anyway, if you have a story in your pipeline that revolves around a real person, you may want to check this decision in more detail.