PDCD1 and metastatic melanoma: Moreover, the programmed cell death ligand 1 (PD‐L1) is highly expressed in tumor cells and APC,[10] and its upregulation is associated with the suppression of the synergic T cell receptor‐CD8 cooperativity, which delays the recognition of the antigen by CD8 T cells.[11] The programmed cell death protein 1 (PD‐1) antibody revolutionized the treatment landscape of metastatic melanoma patients and was more recently approved for a specific subset of CRC patients.