The concept is strange to say the least. Apple filed with theUSPTO (U.S. Patent Office) a patent describing a rather unusual use ofApple Pencil. The stylus could not only be recognized remotely (it would then be possible to launch an application without even touching the screen, via the stylus), but in addition, once placed in a notch located just above the keyboard, the latter could also serve as a second trackpad!
The notch would indeed make it possible to press on the stylus or to make it roll on itself, movements which could be interpreted by the interface macOS like commands for scrolling, scrolling in a menu, selecting an application, etc.
The very unconventional aspect of this technology makes us largely doubt its integration into a marketable product, but after all, Apple is used to thinking outside the box.