Apparently there was a .MOD file format created by Panasonic and JVC to store digital camcorder recordings. (Not to be confused with the .MOD file format used to store music modules.)
https://www.wikihow.tech/Work-with-JVC-.MOD-Files
I'm guessing that that these files are from after the era of tape-based (MiniDV, Digital8) digital camcorders – as the video on their tapes was in DV format. Hopefully that means that your problem is "merely" converting the files and not getting them onto your computer in the first place. (With a MiniDV or Digital8 camcorder, you'd face the issue of modern Macs lacking Firewire and of Apple having discontinued their Firewire adapter.)
The Wiki claims that these .MOD files are MPEG2 files in disguise and that changing the file extension to .MPG may allow other software to see them.
If I remember correctly, MPEG2 is the codec used on DVD-Video discs. It's meant as a final output format, so is not quite as editing-friendly as DV format was.