RET and non-small cell lung carcinoma: Moreover, for NSCLC patients harboring other driver gene mutations such as ROS1, NTRK and RET fusions, FGFR, HER-2, and METex14 mutation or overexpression, immunotherapy in combination with chemotherapy± bevacizumab may be considered an effective and tolerable second-line treatment option, regardless of PD-L1 expression levels,431,432 although concrete evidence is lacking.