Google rolled out a call screening service for android that is basically that. But I don't use it much. If it happens to be a legit call it is a fairly awkward

Google rolled out a call screening service for android that is basically that. But I don't use it much. If it happens to be a legit call it is a fairly awkward interaction - just letting it go to voicemail and calling back seems nicer, and less surprising to the caller. If it is a robocall it really isn't better than voicemail.