Checkpoint blockade of PD-1 or PD-L1, but not PD-L2, at the time of iNKT cell activation (by α-GalCer) increases cytokine production and cytotoxicity in vitro and in vivo, and decreases iNKT cell anergy, B16 melanoma tumor size, and metastatic lesions (54–56). Here, CD274 is linked to neoplasm.