Analysis of tumor cell lines and paired TILs from ICI-treated melanoma patients showed high expression of PVR, TIGIT ligand, and TIGIT in tumor cell lines and tumor-infiltrating T cells, respectively, and functional assays showed that TIGIT blockade or PVR deletion activated T cells (10.1136/jitc-2021-003134). The gene discussed is PVR; the disease is melanoma.