New side channel attacks have been discovered for both 4G and 5G cellular network that can allow attackers to identify a specific person's device and then listen in on calls on specific networks. I have not found a way to protect against this, you could turn off your phone while not in use but then if an emergency occurs...yea.
the attack is called torpedo which means TRacking via Paging mEssage DistributiOn, once the malicious actor has verified your device information they can then launch a piercer attack (Persistent Information ExposuRe by the CorE netwoRk) which will allow them to tie your device to your phone number which they can then use to get call information real time

this has been confirmed to be a vulnerability in every united states cellular network provider




https://threatpost.com/torpedo-privacy-4g-5g/142174/
https://thehackernews.com/2019/02/location-tracking-imsi-catchers.html