Emphasizing an area on a basemap

[SLouq]

I have the world imagery basemap layer in my ArcGIS Pro and have drawn a polygon around the area of my project. What I am trying to do is emphasize the area inside my polygon and make the imagery outside the polygon shaded. Like a transparency on it.

I thought about creating two different map frames and just making one transparent and using the Clip Layers tool on the other but that doesn't seem to work because both map frames take on the same effect. Or maybe get the inverse of my polygon and just shade that part but I'm not sure how to do that.

Any ideas?

[Robert_LeClair · Accepted solution]

Great blog post here from Esri's own John Nelson!  Very creative ideas to be found!

[SLouq]

Thanks! 

What I'm trying to accomplish is the semitransparent overlay and I think this shows how to do it!