PDCD1 and melanoma: We evaluated PS expression together with active caspase-3 by CD8+ TILs and found that the majority of PS+PD-1+Tim-3+ CD8+ TILs in human MM were not apoptotic (i.e., they did not express active caspase-3), in line with previous publications of melanoma and other solid tumors (refs. 21, 23 and Supplemental Figure 1F).