Cellular Cosmetics: How Innate Lymphoid Cells Can Recontour the Tumour Microenvironment

ABSTRACT The innate lymphoid cell (ILC) family includes natural killer (NK) cells, recognised for over 50 years, as well as several more recently identified populations. Over the past 15 years, ILCs have emerged as key orchestrators of tissue homeostasis and inflammation. To build upon the early promise of cancer immunotherapies, it is essential to better understand the pathways regulating the composition of, and immunosuppressive mechanisms that dominate many solid cancers and effectively curtail or block T cell responses. Given their residence within most tissues, how these cellular sentinels influence tumour development and progression remains an active area of both discovery and more translationally focused research. By defining precisely how different immunosuppressive pathways form, rationalised immunotherapy combinations can be devised to specifically target these. Current evidence indicates that for each ILC subset, both pro‐ and anti‐tumourigenic roles are possible, likely reflecting local cues within different tissues and contexts. Here, we seek to concisely review some of the prevailing data describing ILC contributions to tumour immunity and highlight some of the challenges that still exist in fully dissecting these mechanisms.