The IBAction function of buttons placed in custom cells is not called.

As you can see in the comment section, the current status of the questionnaire says, "Well, you should be able to do that.If you actually try it, it's done." All you'll get is a response.With that kind of content, you can't answer, so you have no choice but to say that you can't answer.
I was also able to create an Xcode project based on the information on the Internet (the result of searching by keywords such as "xib tableviewcell"), tap the button on the cell, and run the method set to IBAction.In fact, however, the results were not achieved without any particular difficulties.It is true that I followed the procedure on the site, but the result was that I did not respond even if I pressed the button.
Among the information on the Internet, success stories are as follows:
That is how to make XIB files.Instead of creating an XIB file directly from the File menu in Xcode, New, create an XIB file as an option to create a Cocoa touch class file.(See the picture below, check the Also create XIB file and create a new class file.)

In this way, creating an XIB file saves the XIB configuration in a preset state, preventing misconfiguration and forgetting to configure it.