ICOS and neoplasm: With respect to target engagement, feladilimab exhibited dose-dependent receptor occupancy (Fig. 3E; Supplementary Fig. S1) in A549 tumor-bearing mice and, comparable with our observations with the mIgG1 anti-ICOS mAb in EMT6 tumor-bearing mice (Fig. 3C), significantly increased the CD8:Treg cell ratio in the tumor (Fig. 3F; Supplementary Fig. S1).