GZMK and neoplasm: While anti–PD-1 treatment induced infiltration of exhausted CD8+ T cell (Tex), IFN-γ expressing effector CD8+ T cell (Ifng+ CD8+ Teff) and Gzmk expressing effector CD8+ T (Gzmk+ CD8+ Teff), we observed that loss of Ptdss1 in tumor cells induced a further increase in frequency of Gzmk+ CD8+ Teff cells (Fig. 4D).