We conclude that IL-15/IL-15RαFc + PD-1 blockade activates/disinhibits both CTLs and NK cells, that CTLs and NK cells are the main targets of this therapy, and that CTLs and NK cells are equally required for maximal antitumor response in human solid tumor as demonstrated in our TIL-PDX model of lung adenocarcinoma. Here, IL15 is linked to lung adenocarcinoma.