Moreover, ALK and ROS1 gene tyrosine kinaseinhibitor (TKI) treatment can only be administered to patients with a confirmed generearrangement in the mentioned genes.8–11 Recently, the immune checkpoint inhibitor, pembrolizumab, wasapproved by the US Food and Drug Administration (FDA) in first line therapy forpatients with ≥50% positive PD-L1 expression in NSCLC, as assessed byimmunohistochemistry (IHC).12 The immune checkpoint inhibitor nivolumab can be given to patientswith NSCLC without confirmation of PD-L1 positivity. Here, ROS1 is linked to non-small cell lung carcinoma.