ILC2s and their immune checkpoints in the antitumor response.

Innate lymphoid cells (ILCs) are tissue-resident lymphocytes that patrol mucosal barriers. Among ILC subsets, ILC2s' involvement in the innate immune response to parasites, in the development of asthma and in the repair of damaged tissues is well known. However, their role in antitumor immune response is controversial, as it seems to be dependent on the type of cancer and on interaction with the other cell types in the microenvironment. Immune checkpoint expression and function have been studied recently in ILC2s, with a focus on programmed cell death protein-1 (PD-1) and cytotoxic T lymphocyte-associated protein-4 (CTLA-4). This review summarizes recent progress in understanding the ILC2s' contribution to cancer development and response to immunotherapy targeting inhibitory checkpoints.