This Action formed a network of researchers and clinicians with the aim to establish a gold standard of common protocols and harmonize guidelines for the analysis and clinical monitoring of myeloid regulatory cells (MRCs). There is also a deficit in the translation of findings from animal models to humans, and Mye-EUNITER built an analytical mouse-monkey-man correlation line. Standardized and validated tools for MRC analysis aid the development of cellular biomarkers of disease and guide the design of novel therapies to manipulate the functions of MRCs. Members of the Action from IMR actively engaged in the activities of working groups through attending meetings, workshops, short-term scientific missions, and writing papers.