,4 TNBC is also characterized by a high level of tumor-infiltrating lymphocytes (TILs), high programmed death-ligand 1 (PD-L1) expression, and high median tumor mutational burden, which have been associated, with different levels of evidence, with the response to immune checkpoint inhibitors (ICIs), such as anti-programmed cell death protein 1 (PD-1) and PD-L1 agents.5, 6, 7, 8 This strong biological rationale has led to the development of immunotherapy for TNBC patients, either as monotherapy or in combination with other anticancer agents, including systemic chemotherapy. The gene discussed is PDCD1; the disease is neoplasm.