Indeed, ICIs have renewed the therapeutic approach of several advanced/metastatic forms of cancer leading to the FDA/EMA authorization of anti-Cytotoxic T-Lymphocyte Antigen 4 (CTLA-4) (i.e., ipilimumab), Programmed Cell Death 1 (PD-1) (i.e., nivolumab, pembrolizumab, cemiplimab, dostarlimab), and Programmed Cell Death Ligand 1 (PD-L1) (i.e., atezolizumab, avelumab, durvalumab) monoclonal antibodies (mAbs). Here, PDCD1 is linked to cancer.