Right then, I will start this off by saying I have VERY little information about this as of now.. All I can say is that the latest IOS GO 4 App adds a feature called “Find My Drone” that uses 4G ( and presumably 3G ) as well as WiFi to locate a missing drone. The feature shows “Missing Duration”, “Drone Coordinates”, “Precision Search” and also a couple of options to locate the drone like having the ESC’s beep and the lights illuminate.
The feature seems tied to the aircraft registered with your account and you can choose which aircraft you look for.
Like I said, I have very little info on this as yet but it’s definitely a “THING” DJI is working on. As of now there are no DJI drones that support 4G so it’s with a module for a craft like the MG-1 or Matrice or as yet un documented aircraft ( dare I say Phantom 5 🙂 )..