Major issues of ICI immunotherapy in lung cancer comprise the use of immune biomarker prior to ICI therapy, selection of ICI agents, combination of ICIs/chemotherapy, combination of ICIs/radiotherapy, sequence of tyrosine kinase inhibitor (TKI) targeted therapy and ICI immunotherapy, sequence of chemotherapy and ICI immunotherapy, treatment duration of ICI regimen, and ICI therapy for different histopathology, stage, PD-L1, and performance status. The gene discussed is CD274; the disease is lung cancer.