PDCD1 and neoplasm: Besides governing tumor angiogenesis [97,98], Gal-1 is involved in the emergence of CD8+CD122+PD-1+ Treg cells [99], activation of signaling pathways linked to the epithelial–mesenchymal transition (EMT) process [100,101], acquisition of drug resistance phenotype [102], cancer cell proliferation, migration and metastasis [103,104], among others.