Our previous work has shown that AAV-mediated DNase I liver gene transfer reduces the growth of CRC liver metastases and recruits CD8+ T cells to CRC liver metastasis [22]; therefore, developing combination therapies, such as PD-1 blockade with DNase I treatment, might lead to treatment of cancer patients who receive the least benefit from monotherapy. Here, PDCD1 is linked to colorectal carcinoma.