In recent years, cyber-physical systems (CPS) have emerged as a promising direction to enrich the interactions between physical and virtual worlds. In this article, we first present the correlations among machine-to-machine (M2M), wireless sensor networks (WSNs), CPS and internet of things (IoT), and introduce some research activities in M2M, including M2M architectures and typical applications. Then, we review two CPS platforms and systems that have been proposed recently, including a novel prototype platform for multiple unmanned vehicles with WSNs navigation and cyber-transportation systems. Through these reviews, we propose CPS is an evolution of M2M by the introduction of more intelligent and interactive operations, under the architecture of IoT. Also, we especially hope to demonstrate how M2M systems with the capabilities of decision-making and autonomous control can be upgraded to CPS and identify the important research challenges related to CPS designs.