PDCD1 and cancer: Based on the results of the KEGG enrichment analysis (Fig. 2A), we discovered that oridonin not only affects the signal pathways related to proliferation and metastasis of OS cells, but also participates in the tumor immunity and drug resistance of OS cells, such as EGFR tyrosine kinase inhibitor resistance, platinum drug resistance, T cell receptor signaling pathway and anti-programmed cell death 1 (PD-L1) expression and programmed death-ligand 1 (PD-1) checkpoint pathway in cancer.