PDCD1 and neoplasm: Further analyses identified that the expression levels of checkpoint inhibitors of CD8 + T cells of the tumor microenvironment varied, showing high expression of LAG-3 and low expression of CTLA-4 and PD-1, thus identifying LAG-3 as the predominant checkpoint inhibitor [45], suggesting that dual immune checkpoint blockade with anti-LAG-3 may be the preferred treatment option in uveal melanoma [39].