In murine PDAC, IL-33-mediated TILC2 expansion is accompanied by enhanced intratumoral CD8+ T cell infiltration and PD-1 upregulation in TILC2s, and IL-33 combined with anti-PD-1 treatment can significantly increase TILC2 abundance and reduce tumor volume in both PD-1-sensitive and PD-1-resistant tumors (79). This evidence concerns the gene PDCD1 and neoplasm.