This article presents an overview of state-of-the-art CW, pulsed, FMCW, MIMO FMCW and Doppler radar-based vital sign monitoring of respiration and cardiac activity. Machine learning approaches are explored to identify patterns associated with illnesses that are key to determining treatment. Doppler cardiogram (DCG) monitoring experiments proved this to be an effective contactless approach to detect cardiovascular disease. DC-coupled CW radar approaches are effective for sleep-monitoring to detect respiratory sleep disorders. MIMO FMCW radar and 4D cardiac beamforming techniques are discussed that illustrate the cutting edge of respiratory and cardiac activity monitoring, and experiments proved this technology effective for monitoring across various sleep positions.