PDCD1 and non-small cell lung carcinoma: Furthermore, low-dose (2 Gy/4 fractions/2 days in the first four cycles of therapy) or hypo-fractionated (24 Gy/3 fractions in the first cycle only) radiotherapy did not increase overall response rates of PD-L1 plus CTLA-4 therapy in patients with NSCLC resistant to immunotherapy targeting for PD-1 axis22.