In addition, several reports have shown that PD-L2 overexpressing breast tumors have an enriched epithelial–mesenchymal transition signature, crosslinking immune evasion and EMT [70], whereas in osteosarcoma cells, PD-L2 promotes tumor invasion and metastasis through the RhoA-ROCK-LIMK2 pathway [71], highlighting the importance of this ligand as a potential therapeutic target. Here, PDCD1LG2 is linked to osteosarcoma.