With the advent of immune checkpoint inhibitors (ICI) in solid tumors, multiple studies in mesothelioma showed some promising results with anti-programmed cell death protein 1 (anti-PD1) or anti-programmed death-ligand 1 (anti-PD-L1) inhibitors as a single agent or in combination with anti-cytotoxic T-lymphocyte-associated protein 4 (anti-CTLA4) inhibitor [12,13,14,15,16,17]. The gene discussed is PDCD1; the disease is mesothelioma.