What makes a "MacGuffin" different from a "red herring"?

A macGuffin is an item in a movie that is seen and talked about, but the viewer doesn't know what it is or what it has to do with the plot. A red herring is a deceptive item in a movie that is used to throw someone off from the actual item.

https://medium.com/illumination/red-herring-narrative-technique-what-is-a-red-herring-f0778332ca4a

A MacGuffin is usually a physical object or objective. It drives the plot forward.

A Red Herring is a clue or the identity of a character. It distracts and misleads the viewer or reader from the plot and has little or no bearing on the outcome.

The fundamental difference is that a MacGuffin drives the plot forward by motivating the characters, while a red herring intentionally misleads the audience. A great way to separate them is to look at who is being affected: a MacGuffin is what the characters chase, whereas a red herring is a false trail that the reader or viewer chases. Popularized by legendary filmmaker Alfred Hitchcock, a MacGuffin is ultimately a hollow tool. It doesn't matter what the object actually is-it could be a diamond, a top-secret microfilm, or a magical artifact-as long as the characters desire it enough to fight over it. As the film goes on and the real emotional or physical stakes heighten, the MacGuffin itself is often completely forgotten by the audience. Originating from the practice of using pungent, smoked kippers to train scent hounds, a red herring drags the audience's attention away from the actual truth. Writers-especially in the thriller and mystery genres-drop these plausible clues so that the eventual conclusion catches you off guard. Once a red herring is exposed, it loses all relevance to the forward momentum of the story.