The IC50 value for PD-1/PD-L1 inhibition was determined by analyzing the log of the concentration-response curves to fit a sigmoid curve with four-parameter logistic (4PL) regression using the GraphPad Prism Software version 8.3.0 for Windows, GraphPad Software, La Jolla California USA, www.graphpad.com. The IC50 values are provided in Table . Following equation defines the regression curve.