Furthermore, patients who received anti-CTLA-4 antibodies prior and continued to receive anti-PD-1 antibodies had more tumor mutation burdens than patients who did not experience anti-CTLA-4 therapy, which means an increase in the number of non-synonymous mutations in the genome of tumor cells that may lead to the production of neoantigens that activate the immune system’s attack on tumors. Here, PDCD1 is linked to neoplasm.