PDCD1 and neoplasm: When ferroptosis induction is combined with PD-1/PD-L1 blockade, interferon-gamma (IFN-γ) released by activated CD8+ T cells can promote ferroptosis of tumor cells by inhibiting system xc-, establishing a positive feedback loop between ferroptosis and immune responses to enhance the synergistic effect on curbing tumor progression and metastasis 89.