Which CLI command displays the physical media that are connected to ethernet1/8?

The CLI command "show system state filter-pretty sys.sl.p8.phy" is used to display detailed physical layer information, which would include the physical media connected to a specific interface such as ethernet1/8. This command is designed to filter the output to show relevant physical layer information for the specified interface.

For more information on Palo Alto Networks CLI commands and their outputs, refer to the "PAN-OS® CLI Reference Guide".