To confirm this hypothesis, in the TGF-β-rich 4T1 tumor model we found that TGF-β blockade using neutralizing anti-TGF-β mAb restored the 4-1BB-elicited potent antitumor activity as comparable to anti-CD73 monotherapy (Fig. 5e, f), whereas neither anti-TGF-β or anti-4-1BB alone was able to inhibit tumor growth (Fig. 5e, f). Here, TGFB1 is linked to neoplasm.