However, it is important to realise that ILC2s also express inhibitory checkpoint receptors such as PD-1, and therefore systematic administration of immune checkpoint inhibitors may simultaneously precipitate pro-tumoural functions of ILC2s particularly in cancer types such as CRC and lung cancer where ILC2s are found to promote tumorigenesis [4, 5, 65, 66]. Here, PDCD1 is linked to lung carcinoma.