Given that anti-PD-1 therapy has only a modest influence on the number of TILs in melanoma,41 42 the growth of melanoma might be additively regressed by the combined effects of 1) increased T cell-mediated cytotoxicity by inhibiting PD-1 and/or LSP1 and 2) enhanced T cell motility by Lsp1 deficiency. The gene discussed is PDCD1; the disease is melanoma.