Each year on January 1, copyrights that are 95 years old expire. It was 95 years ago, in 1927, when the last Sherlock Holmes stories were published. (Copyright laws vary by country. In the U.S., copyrights expire after 95 years.)
Those who profit from copyrights will attempt all sorts of novel legal arguments to keep the profits going. Think Mickey Mouse and Beatrix Potter, as well as Sherlock Holmes. Duke University’s Center for the Study of the Public Domain is one of the few institutions that track the public interest in copyright laws. Here is a link to their post on Public Domain Day 2023, with a list of some of the books, movies, and songs that are in the public domain as of today.