CTLA4 and osteosarcoma: Osteosarcoma may be unlikely to benefit from targeting inhibitory ICs like CTLA-4, PD-1 and OX40 alone [58] Based on our canine IC expression heatmap and human literature, we suggest that B7-H3, a complex-function IC molecule associated with poor prognosis [63] that is highly expressed in both human and canine OS, might be a potential therapeutic target worth investigating in a comparative oncology framework.