Shake reduction vs. unsharp mask in PSE 2018?

melissab99736742  wrote Can anyone tell me the difference between these two features?

I suggest to read the help file:

Sharpen photos

and to come back here for more detailed questions.

In summary, shake reduction works on parts of the image with have been blurred by camera shake or movement of the subject.

Unsharp mask in a method to work on edges and details to create more contrast between the edges.