A study based on the intrinsic link between the degree of PD-L1 expression on tumor cells and the type of KRAS mutation found that, as a PD-1 inhibitor, pembrolizumab, or an ERK inhibitor can restore the body’s antitumor immunity and prevent apoptosis of CD3+ T cells by preventing the immune escape of tumor cells (85). This evidence concerns the gene PDCD1 and neoplasm.