Preclinical data showed that the stimulatory activity of PD-1-targeted IL-15 mutein was enhanced in tumor-infiltrating lymphocytes (TILs) preferentially over peripheral lymphocytes, leading to greater antitumor activity compared with anti-PD-1 and IL-15 agonist alone or in combination even in immunologically cold tumors that are not typically responsive to anti-PD-1 therapy.24 This evidence concerns the gene PDCD1 and neoplasm.