CD274 and neoplasm: Practical identifiability analysis was then performed, and results show that murine data on tumor, T cells, and MDSCs over the course of six time points was able to identify five parameters, namely the tumor growth rate (λC), the T cell kill rate (η), the inhibition rates by PD-L1-PD-1 (ρ) and by MDSCs (r), and the MDSC death rate (dM).