CD8A and neoplasm: In 2015 Sivan et al. compared the growth of subcutaneous melanoma between C57BL/6 mice obtained from two vendors (JAX and TAC) which are known to differ in their commensal microbes.25 They revealed that tumors in TAC mice grow faster and are less sensitive to anti-PD-L1 antibodies compared with JAX mice, and these differences were associated with lower intratumoral infiltration of Cd8 + T cells and weaker tumor-specific T cell response.