Google Nexus and Android One smartphones will soon come with spam caller protection, thanks to an update to Google's stock Phone app. Spam protection will alert users if an incoming call is a suspected spam caller and allow them to block and report the number.
Spam protection will be available on Nexus and Android One devices once users update to the latest version of Google Phone, which is being pushed out as of press time. For now it looks as though only 'pure' Android devices are getting the feature, meaning while Galaxy S7 and HTC 10 users will miss out, you can probably expect it to come baked into the upcoming 2016 HTC Nexus by default.
Caller ID and spam protection should already be enabled on compatible devices, although you can check by opening the Phone app, tapping the button with the three dots in the top right corner and then hitting 'Caller ID & Spam Protection'. From here you can toggle the setting on and off.
Once this feature is enabled, incoming calls suspected of being spam will displayed in red with a warning beneath the number. To mark a number as spam, go to the call log, tap the number you want to mark and hit 'Block / report spam.' You'll then have the option of reporting and/ or blocking the number. If you accidentally report a genuine phone number as a spam caller, you can unmark it by following the same steps.