The McGuffin has been a powerful storytelling device for a long time. It was Alfred Hitchcock who popularized both its use and the name that sounds like it should be on a dollar menu.
The McGuffin has a cool job: to keep the plot, character, or situation rolling along. It draws us into the story and drives the action. The McGuffin is often an object of high value, which everyone covets. It can be ambiguous, entirely undefined, generic, or left open to interpretation.
Remember the suitcase in “Pulp Fiction?” Classic McGuffin. Though it showed up a few times throughout the film, and was important enough to get a handful of people peppered with bullets, we never actually saw what was in the suitcase.