With respect to the use of anti-PD-1 antibody for the treatment of osteosarcoma, there only exist three interim reports on clinical trials (Liao et al., 2017[31]; Shen et al., 2014[54]; Veenstra et al., 2018[63]) and one basic research report (Zheng et al., 2015[73]). This evidence concerns the gene PDCD1 and osteosarcoma.