CD8A and neoplasm: Recently, some preclinical studies showed that fruquintinib could enhance the anti-tumor efficacy of PD-1/PD-L1 inhibitors for treating MSS-metastatic CRC by decreasing angiogenesis, reprograming the structure of vessels, and increasing the infiltration of CD8+ T cells, CD8+TNFα+ T cells, and CD8+IFNγ+ T cells in the tumor microenvironment (21, 22).