Phospholipids regulate immune cell functions through both intracellular and extracellular mechanisms, engaging lipid-modifying enzymes, cell surface receptors, and lipid mediators such as lysophosphatidic acid (LPA), sphingosine 1-phosphate, and prostaglandins. In a recent study published in Immunity, Ping et al.1 have investigated how phospholipid metabolism impacts the antitumor functions of CD8+ T cells within the tumor microenvironment (TME). They report that PD-1 signaling downregulates the expression of phospholipid phosphatase 1, termed PLPP1 (hereafter referred to as LPP1, formerly PAP-2A), which contributes to ferroptosis of intratumoral CD8+ T cells.