CD274 and neoplasm: So far, mismatch repair deficiency (MMR), programmed cell death-ligand 1 (PD-L1), tumor mutational burden (TMB), and gut microbiota (GM) features [8, 13–15] have been regarded as the best available biomarkers to predict the efficacy of ICIs, but they are confronted with some limitations, including high cost, obstacles in obtaining tissue samples, and lack of robust prognostic accuracy.