CRP and nasopharyngeal carcinoma: We developed an immune response index (IRI) integrating C-reactive protein (CRP) and lactate dehydrogenase (LDH) to address this need.<h4>Methods</h4>In 209 RM-NPC patients receiving PD-1 inhibitor monotherapy, we constructed a pretreatment IRI using baseline CRP and LDH, and an on-treatment IRI based on their early kinetic changes.