TNFRSF18 and neoplasm: Given that Tregs are a significant source of immunosuppression in the tumor microenvironment, and that the proportion of the Treg subset among TIL in the combination treatment group was not diminished relative to the control (Fig. 1c), we hypothesized that the ratio of effector T cells to Tregs was elevated in the anti-GITR (1)/SRS group relative to the control.