High-precision optical frequency combs, often called optical rulers, have had a tremendous impact on metrology and spectroscopy in recent years. Advanced fabrication technology of optical microcavities or microresonators has enabled the development of microcombs that have dramatically amplified the optical field and are at the frontier of new optical sources and applications. With the support of the Marie Skłodowska-Curie Actions programme, the MICROCOMB project is training a new cohort of researchers in disruptive microcomb technology to establish a leadership position for Europe and enhance its competitiveness in this rapidly growing field.