IL15 and neoplasm: Administration of IL-15 as a sole immunotherapy agent in a clinical trial resulted in a significant increase in the number of circulating group 1 ILCs [77], however, anti-tumour efficacy was limited due to the presence of inhibitory immune checkpoints which limit group 1 ILC function, a lack of tumour-specific targeting by the group 1 ILCs and lethal autoimmunity at high doses [21].