This paper provides an overview of recent developments in Joint Communication and Radar Sensing (JCRS) systems and networks. Our discussion will focus on radio system and network architectures that can be used for JCRS and on approaches to select, generate and process waveforms suitable for both communication and sensing. In addition, advantages and challenges of assembling a network out of several JCRS nodes are addressed. Finally, we give an outlook to possible applications of JCRS networks, which we see in autonomous driving and low altitude air traffic control.