After chemotherapy, immune checkpoint inhibitors are the second-line treatment for NSCLC patients with high PD-L1 (programmed death-ligand 1) expression. However, the overall response rate is only about 20-30%, and for patients who failed immunotherapy, how to choose a suitable following treatment remains unknown. Therefore, researchers constructed a retrospective study with 82 stage IV NSCLC patients to investigate whether patients who have failed immunotherapy have better responses to salvage chemotherapy. The results demonstrated that the partial response rate to salvage chemotherapy is much higher in patients who were pretreated with immune checkpoint inhibitors than in the control group (27% vs 7%). Although those results should be further confirmed in a larger prospective study, these findings imply that immunotherapy, by activating the immune system and influencing the tumor microenvironment, renders tumor cells more sensitive to the following chemotherapy. These findings may guide a new treatment strategy for NSCLC patients.