Hello, actually Holmes has a prototype. The prototype of Sherlock Holmes, according to Doyle's own narrative in The Truth of Sherlock Holmes, is based on his medical school tutor Dr. Bell (that is, Professor Bell, who is usually translated by China). However, even Bell himself doesn't seem to like this statement. Personally, I think Doyle misled the readers at the request of the real prototype.

I think Shylock may really exist in London. Of course, the detective's name is not Sherlock Holmes, and he doesn't live at 22 1B Baker Street, but he is probably a friend of Sir Doyle, and he also does similar "consulting detective" work with Sherlock. In other words, I think Sherlock Holmes comes from a real prototype. His personality may not be as distinct as Sherlock Holmes's, and his deduction may not always work, but there is a genius detective in London. Sherlock's most important cases-The Four Signs, The Hound of the Baskerville, The Scarlet Letter and most of the cases in the history of adventure may be the case records of this real detective. More than half of the cases in The Story of the Return and The New Survey are probably made up by Conan Doyle. Especially in the late stage of the new investigation, Doyle may have fabricated all the cases. There are two possibilities. One is that the real detective died, or he really retired like Sherlock later. At that time, Conan Doyle signed a serial contract with the newspaper, so it was impossible to stop writing halfway and had to make up. And several seemingly bad stories in the history of venturing back are probably made up because there were no good cases to write at that time.

References:

baike.baidu.com/view/96072.htm