In recent years, single-atom catalysis has become a major research focus in heterogeneous catalysis. In these systems, the absence of ensemble effect and the existence of strong electronic effects of the support induce a reactivity very different from that of the metal particles. Single-atom catalysts can be present in many supported catalysts (including commercial ones) in combination with metal nanoparticles, and have certainly played an important role in many catalytic processes, but they have rarely been recognized as active sites. In this context, the COMET project aims at developing a new generation of supported catalysts, combining in a controlled manner isolated atoms and metal particles, in order to achieve a cooperative catalysis for continuous flow reactions. In this cooperative catalysis, isolated atoms and particles participate in the facilitation of reactions that would be less favorable on a single type of site. Preliminary results obtained by COMET project partners strongly support this innovative approach.