Immunotherapy with immune checkpoint inhibitors (ICIs) such as anti-cytotoxic T-lymphocyte associated protein 4 (anti-CTLA4) and anti-programmed cell death protein 1 (anti-PD1) reverse the exhausted anti-tumor immune cell responses and has given a tremendous hope in terms of survival for metastatic cutaneous melanoma (mCM) patients in the clinic (12, 13). Here, PDCD1 is linked to neoplasm.