AT&T is not usually one to leave money on the table, but in a rare showing of benevolence, it has launched a new service called Call Protect. It can be activated free on AT&T devices, allowing you to block numbers and get warnings of potential spam calls at the network level.
There are three main features included in Call Protect. Most important of all, known fraud numbers will be automatically blocked from ringing your phone at all. Next, suspected spam callers will be identified before you pick up. You can still choose to answer, but at least you'll know. Lastly, there's the manual number blocking feature. Numbers you add to your block list are only good for 30 days, at which point you have to renew the block. That seems a little weird, but it's more than most carriers will do.
Call Protect is available to users with standard postpaid plans that have support for HD Voice (almost all smartphones AT&T has sold in recent years have this). Several of these features will only work when you're in an HD voice coverage area too. Just install the app to get started.