These potential factors include PD-L1 expression, tumor-infiltrating lymphocytes, gene mutation (BRAF, EGFR, KRAS and DNA mismatch repair related genes), blood immune biomarkers (such as IL-18, ITAC, IFN-γ, IL-6) and patients' life style such as smoking history, etc. The details of these factors are listed in Table 2. Here, KRAS is linked to neoplasm.