Myeloid cells are a major component of immune cells infiltrating tumors, interacting with each other, with tumor cells and other stromal cells, and demonstrating a prominent plasticity. Tumor-associated myeloid cells, such as neutrophils (or so-called MDSCs: suppressory neutrophils) contribute to cancer progression via multiple mechanisms. Neutrophils are the most abundant myeloid blood cells, which have been shown to exert heterogeneous phenotypic and functional states: reaching from anti- to protumoral. On the one hand these cells can suppress anti-tumor immune responses, support tumor angiogenesis or metastatic dissemination. On the other hand, neutrophils actively kill tumor cells, or activate T-cell dependent immune responses.There is still little information on tumor-infiltrating neutrophils and their clinical relevance. Nevertheless, neutrophils were demonstrated to be associated with poor clinical outcome in patients with different kinds of cancer, including renal cancer, non-small-cell lung carcinoma, melanoma and head and neck cancer. Enrichment of neutrophils was also associated with metastases in various tumor entities. The recruitment of neutrophils within the tumor microenvironment is strictly regulated by chemokines, such as CXCL2 or CXCL8/IL-8.Neutrophil activity strongly depends on the stimulus present in the microenvironment. Since these cells are highly plastic and can easily alter their functionality, they are an ideal target for designing anti-tumor therapies. However, most of therapeutic strategies to target neutrophils in tumor-bearing hosts are dealing with the blocking of their migration into the tumor site. The efficiency of such approaches is, however, limited, as it does not address heterogeneity of these cells, and thus depletes as well antitumoral cells, leading to cancer progression and infectious complications.Given a critical role of neutrophils in tumor progression, we tested several alternative strategies to neutralize pro-tumoral activity of these cells, including reprogramming and inhibition of their immunosuppressive functions. Our recent data using own designed CCL2 peptide MyeloMIB show promising therapeutic results in head and neck cancer preclinical models. Application of this peptide leads not only to the specific inhibition of neutrophil migration into tumor tissue, but also reprograms these cells into anti-tumoral state. These results suggest a dual-edged role of neutrophils as essential regulators of anti-cancer immune responses and argue for approaches fostering anti-cancer activity of these cells, not only their migration, during cancer immunotherapy.