In a meta-analysis of 20 RCTs investigating PD-1 inhibitors across different tumor types (including 12 melanoma studies, five NSCLC studies, and three RCC studies), which involved a total of 4496 unique patients, the occurrence of grade three or higher pneumonia was found to be between 0% to 4.3% and 0% to 10.6% for any grade of pneumonia. Here, PDCD1 is linked to susceptibility to pneumonia measurement.