Pharmacological inhibition of caspase-8 by z-IETD-FMK robustly reduces tumour outgrowth and this is closely associated with a reduction in the release of pro-inflammatory cytokines, IL-6, TNF-α, IL-18, IL-1α, IL-33, but not IL-1β. Furthermore, inhibition of caspase-8 reduces the recruitment of innate suppressive cells, such as myeloid-derived suppressor cells, but not of regulatory T cells to lungs of tumour-bearing mice.