CD274 and neoplasm: In addition, changes in the tumor microenvironment have also been found to be correlated with drug resistance; Mikami et al. (2019) detected upregulated expression of PD‐1 and PD‐L1 in tumor‐infiltrating immune cells (TIIC) in the tumor microenvironment, related to the resistance of vascular endothelial growth factor‐tyrosine kinase inhibitors (VEGF‐TKIs).