In two studies analyzing anti-PD-(L)1/CTLA-4 combination therapy in NSCLC and SCLC, both of which yielded a higher ORR than PD-(L)1 monotherapy, high TMB was the main indicator for success [130, 131], possibly explaining why the combination succeeded in MMR-deficient colorectal cancer, which typically exhibits an elevated TMB. The gene discussed is CTLA4; the disease is non-small cell lung carcinoma.