At least in my country, incoming call filters do wonders, in particular those which query the incoming number at an online database to show you who's the caller.
Not sure about elsewhere, but in the US, it is possible to spoof phone numbers. The only way to verify that the person you are talking to is actually associated with the number is to hang up and call them back. This is particularly a problem for companies like banks and insurance.
Android actually does provide some amount of filtering[1], but if someone, say, spoofs a seemingly legitimate number, it will come through fine.
I've seen similar applications for ios, but they all seemed to want permissions I wasn't so happy to give to some rando. If apple provided the service, I'd probably be okay with it, but I'm not super comfortable feeding my entire contact list and all my call metadata to some random third party
