With the large adoption of small and smart objects, the Internet of Things (IoT) enables a large and universal access over a very heterogeneous set of devices. More specifically, the Industrial IoT (IIoT) aims to provide a wireless infrastructure for industrial applications, relying on time‐critical flows. However, radio communications are known to be lossy, with time‐variant characteristics. Thus, providing ultra high reliability with very stringent end‐to‐end delay constraints is particularly challenging. This special issue is thus dedicated to the challenges and solutions raised by the specific constraints of the IIoT.