unable to import photo from my camera

ok guys! many thank to you all, I solved the problem simply by resetting the preference file that was corrupted. Resetting the Preference file can fix odd behavior, to do it you have to restar LR pushing SHIFT + OPTION (on MAC) this will reset preferences and then you must restart LR... very simple but you have to know it!

As I previously said the problem does not only concern the camera or SDcard but also all the other folders. In the import module I can't see any file, any type of file: no raw, no jpeg, new or old files that are.I think it is a problem concerning the import module or some configuration that I cannot understand. When I try to import the same photos through LR cloud based all this does not happen so I can see all the photos even those already imported in the catalog (that appear obscured).

Now a experiment

In Finder copy some image that has never ever been in Lightroom to a folder that your Lightroom catalog shows in Lightroom Classic Folder panel.

Just download something from the internet. JPEG, TIFF, whatever.

Then, bring up Lightroom, bring up Import, in the File section, not Device, navigate to the folder you put that image in. Does the folder show up on the left?

Then up top select ADD.

Does the image show up in the grid view?

Note this experiment ignores the camera, ignores the SD card on purpose.First step first

I quote "P.S. outside of Lightroom, in Your OS file manager, in your case Finder,  do you see the SD card?" NO, I don't know the reason 

If you cannot see the SD card in your camera in Finder, then Lightroom will not see it. You need to resolve what is going on with that.

maybe I did not explain well. I cannot see the files to be imported from the camera, and this is a fact, but I cannot even see the files to be imported into the catalog (or to be copied or moved to another destination, it is the same problem) that are stored on the hard disk or on other media, despite of the destination that I choose. in essence, nothing is displayed in the import module.

I quote "P.S. outside of Lightroom, in Your OS file manager, in your case Finder,  do you see the SD card?" NO, I don't know the reason 

Usually I'm used to import directly from the card in the camera. I'm still able in 8V to see the camera as source visible both in the upper right corner of the page and in the file tree on the left, but as you can see pics files aren't shown.

Ok, this concept of looking for imports under devices, Stop that, Adobe does not want that route any more. Why? Because of problems just like this.

Move your mouse down to the section that states  File, Navigate in File to find the hard drive that us your SD card. Not your camera.

P.S. outside of Lightroom, in Your OS file manager, in your case Finder,  do you see the SD card?

Quote "I'm still able in 8V to see the camera as source visible both in the upper right corner of the page and in the file tree on the left, but as you can see pics files aren't shown."

I do not understand why the Camera would show in the right-hand side, that's where you would choose the Destination Folder to copy the files to. What I would like to see a screen capture that shows the Left Panel where you would choose the source files to import.

The screen capture is so small I cannot read it, however, I can see that you have selected "Copy" but I cannot determine if you have selected the Camera Card in the left panel. In one of my earlier posts, I included a screen capture showing the camera as an external device with the camera card folder selected. See the screen capture from the earlier post.

Usually I'm used to import directly from the card in the camera. I'm still able in 8V to see the camera as source visible both in the upper right corner of the page and in the file tree on the left, but as you can see pics files aren't shown.

@ DavidG quote" And if from the card in the camera, do you see that as a drive in the import source screen? Adobe has abandoned showing devices."

I do not normally import from my camera, but I did so yesterday to check what the OP was doing, my Camera was recognised by my iMac via a USB connection. I was able to import from the SD card in the Camera.