ISO file

AFAIK, macOS does not have or use any .iso files so it must be a file that you (or someone who uses/used your computer) downloaded to the drive. Any file you place on the drive or is within the main visible area of your home user folder usually is fair game to delete since it has either been download or created by the user (or someone who uses the Mac). macOS is unable to open many .iso files if they are images for non-Apple operating systems, although the file names usually give a clue to what is contained in the .iso file. Just because macOS is unable to open an .iso file does not mean the .iso file is broken or damaged.

Assuming you are backing up using Time Machine then it should be find to move it to the Trash. If for some reason it creates a problem then use Time Machine to restore the file.

What is the ISO file of?????????????