The review discusses the data on the functional/phenotypic M1/M2 types of macrophages and their chimeric forms, the molecular mechanisms of polarization of these cells, and their role in the development of malignant tumors. Information on the prognostic value of the presence (density and location) of M1/M2 cells in tumor tissue is analyzed. Our own results evidence on the necessity of determination of the functional/phenotypic state of M1/M2 macrophages from different biological niches in the dynamics of tumor growth, in particular in terms of NO level and arginase activity.