PDCD1 and cancer: As an instance, The often-used TMB may fail to predict the potency of combined anti-Programmed Cell Death 1 (anti-PD-1) and anti-Cytotoxic T-Lymphocyte Associated Protein 4 (anti-CTLA-4) treatment in a number of cancer varieties (4), underscoring the necessity to establish robust markers and optimize biomarker combinations.