PSGL-1 Attenuates Early TCR Signaling to Suppress CD8⁺ T Cell Progenitor Differentiation and Elicit Terminal CD8⁺ T Cell Exhaustion

PSGL-1 deficiency empowered CD8+ T cells to respond to low-affinity T cell receptor ligands and inhibited growth of PD-1-blockade-resistant melanoma by enabling tumor-infiltrating T cells to sustain an elevated metabolic gene signature.