Based on the results of a biomarker analysis reported at the 2021 World Conference on Lung Cancer, the abundant expression of genes in the major histocompatibility complex class II antigen-presenting pathway was predictive of the response to sintilimab plus chemotherapy, regardless of the PD-L1 expression status, and is a predictor of treatment response, in addition to tumor PD-L1 expression and tumor mutational burden (55). The gene discussed is CD274; the disease is lung carcinoma.