Therefore, we designed a prospective observational study aimed at evaluating the prognostic or predictive role of cachexia (with related changes in the inflammatory, immunological, and nutritional parameters) on the survival (progression-free survival [PFS] and overall survival [OS]) and clinical response (i.e., disease control rate) to anti-PD-1 inhibitor-based monotherapy in patients with advanced NSCLC. The gene discussed is PDCD1; the disease is non-small cell lung carcinoma.