TNFRSF9 and neoplasm: A single-cell RNA-sequencing (scRNA-seq) analysis of CD45 + TILs in MC38 tumours revealed that both the two classes of T cells (class I and class II) and NK cells were increased in the IBI319 and αPD-1 + αCD137 mAb combination treatment groups in comparison to the αPD-1 treatment group, suggesting that the contribution of CD137 stimulation to efficacy is mainly mediated through T and NK cells (Fig. 3c, d; Supplementary Fig. 4).