CD8A and neoplasm: Interestingly, the ferroptosis pathway was found to be enriched in PMN-MDSCs in colorectal cancer liver metastasis using single-cell transcriptome analysis.2 Kim et al. further reported that the spontaneous ferroptosis of PMN-MDSCs in the tumor microenvironment triggered the secretion of PGE2 and the release of oxidized phospholipids, rendering them more immunosuppressive by influencing the activity of CD8+ T cells and tumor-associated macrophages (Fig. 1).