IDO1 and non-small cell lung carcinoma: Nevertheless, in a study that enrolled 891 non-small cell lung cancer (NSCLC) samples, Bessede et al. noted that combined anti-PD-1/PD-L1 targeting of IDO1 might only be beneficial in patients with inflammatory tumors, and that the IDO1 pathway in NSCLC is driven by the immune system rather than tumor cells [64].