All mods used are listed on each of the maps steam page. Try unsubscribing and resubscribing to all.

I soon realized I needed additional prop mods that were linked in the map files. So just clicking "subscribe all" on the collection packs of both Iwo Jima and Okinawa is not enough.

Anyway, the maps look great. Looking forward to do a full play-through of each mission set.

When I try to play missions from this campaign or your Iwo Jima campaign, it shows that it's downloading a mod on the loading screen, then sends me back to the main menu with an error message. I subscribed to everything in both collections.