Inventors have generated two human anti-cath-D scFv fragments cloned in the human IgG1 format (F1 and E2) that efficiently bind to human and mouse cath-D, even at the acidic pH of the TNBC microenvironment. F1 and E2 accumulated in TNBC MDAMB- 231 tumor xenografts, inhibited tumor growth and improved mice survival without apparent toxicity. Using this xenograft model, they found that the Fc function of F1 was essential for maximal tumor inhibition. Inventors have shown that the anti-cath-D antibody F1 treatment prevented the recruitment of tumor-associated macrophages and myeloid-derived suppressor cells within the tumor, a specific effect associated with a less immunosuppressive tumor microenvironment. Moreover F1 inhibited tumor growth of TNBC patient-derived xenografts (PDXs). This preclinical proof-of-concept study validates the feasibility and efficacy of an immunomodulatory antibody-based strategy against cath-D to treat patients with TNBC. Accordingly, the present invention relates to an anti-cath-D antibody which inhibits the tumor recruitment of immunosuppressive tumor-associated macrophages M2 and myeloid-derived suppressor cells for use in the treatment of cancer.