Considering the totality of the recent data in the field, tTMB and bTMB are relatively weak predictive biomarkers for first-line treatment of NSCLC in chemotherapy-free combination immunotherapy or monotherapy settings but may still be of value in patients whose tumors do not express high levels of PD-L1 or in the case of patients who have high bTMB and inadequate tissue for PD-L1 testing19. The gene discussed is TMEM200B; the disease is non-small cell lung carcinoma.