Given the contribution of expanding the understanding of the plasma PD-L1 mRNA expression and exploring its prognostic value in immunotherapy in patients with gastrointestinal tumor, the present study investigated the correlation of PD-L1 mRNA expression in blood and paired tumor tissue specimens, compared the consistency of IHC and quantitative RT-PCR (qRT-PCR) test, and further inquired about the relationship between plasma PD-L1 mRNA expression level and the response to the immunotherapy. The gene discussed is CD274; the disease is neoplasm.