According to another study, which evaluated the variations of sEV PD-L1 protein level before and months after anti-PD-1 therapy (median interval was 4.5 months) in 100 melanoma patients, a decrease in sEV PD-L1 after treatment is associated with response to treatment, while a high increase in sEV PD-L1 is associated with tumor progression4. Here, PDCD1 is linked to neoplasm.