Moreover, although PD-1 deficiency does not significantly affect ILCp frequencies in the bone marrow or the development of mature ILCs in homeostatic conditions132,133, PD-1 is upregulated on lung ILC2s in lung inflammation, and ILC3s express functional PD-1 in the murine intestine130 human decidua134, and pleural effusions of patients with tumors135 . The gene discussed is PDCD1; the disease is Pleural effusion.