No response from thumb drive on MacBook Pro

You don't provide much information. What is the exact model of Mac and version of macOS? You can get this information by clicking the Apple menu and selecting "About This Mac".

Also, what is the exact make & model of the thumb drive and file system used on the thumb drive?

What system or device put the pictures on this thumb drive? And what systems have used this thumb drive since the last time it was formatted (aka erased)?

How are you connecting the thumb drive to this Mac? Are you connecting the thumb drive directly to the laptop or are you connecting it to an adapters, dock, or hub? Try disconnecting all other devices from the laptop in case one of them is causing a problem. Connect the thumb drive directly to the Mac.

Try booting into Safe Mode to see whether the thumb drive mounts while booted in Safe Mode.

Do you have any other computers which you can use to verify the thumb drive can be accessed?

Do you have the Finder preferences/settings configured to show mounted volumes? Do you have any other external drives and can you access them on this Mac?

Hello Cabbie1954,

If you need help importing photos from your storage device to your Mac, see the steps below from: Import photos from storage devices and DVDs using Photos on Mac

"Import from a card reader or SD card

Some Mac computers have built-in SD card slots. If yours doesn’t, you can connect a device called a card reader that is compatible with your Mac and use it to import photos from a memory card, such as an SD or Compact Flash card.

1. Insert the card into your computer’s SD card slot, or connect a card reader to your computer and insert the card into the card reader.
2. In Photos, choose File > Import, then select the photos or videos you want and click Review for Import.
3. Note: If you participate in an iCloud Shared Photo Library, click the Library pop-up menu in the toolbar and choose the library to import into.
4. If you selected multiple photos or videos, do one of the following:

• Import all new photos: Click Import All New Photos.
• Import a selection of photos: Click the photos you want to import, then click Import Selected.

1. If a message asks whether you want to delete or keep the photos on your card after importing them, click Delete Items or Keep Items. 
2. Photos then imports your photos and videos. To cancel importing, click Stop Import.
3. When all photos have been imported, eject the card from your computer or card reader.

Imported photos appear in the Imports and Photos albums in the sidebar.

Some card readers may not be compatible with Photos. For more information, check with the device’s manufacturer."

Cheers.