PDCD1 and neoplasm: The percentage of PD-1+ ILC2s significantly increased after B16 inoculation, from a mean of 15% PD-1+ ILC2s to 60% PD-1+ ILC2s, demonstrating B16 melanoma induces PD-1 expression on pulmonary ILC2s and may subsequently alter anti-tumor effector function (Figure 1D).