PDCD1 and nervousness: Abbreviations: CCI - Charlson Comorbidity Index; ECOG PS - Eastern Cooperative Oncology Group performance status; IQR - interquartile range; LDH - lactate dehydrogenase; M1a - metastases to skin or distant lymph nodes; M1b - pulmonary metastases; M1c - non-central nervous system (CNS) visceral metastases; M1d - CNS metastases; n - number of patients, Anti-PD-1 Ab - anti-programmed cell death 1 antibody