To elucidate whether RCE plus Oxa would affect T cell-mediated cancer cell destruction, we set up co-culture systems using the hPD-L1 MC38 CRC cells and the hPD-1 tumor-infiltrating CD3+ T cells, which were isolated in MC38 tumor tissues of human PD-1/PD-L1 MC38 tumor-bearing mice as target cells and effector cells, respectively. Here, PDCD1 is linked to colorectal carcinoma.