CD8A and neoplasm: As a 4-1BB agonist, HuB6 increased the proliferation of CD8 + T cells and the production of the antitumor cytokine IFN-γ, inhibited tumor growth in all the mouse models tested, induced potent antitumor immune memory and exerted an enhanced tumor-inhibiting effect in combination with an anti-PDL1 mAb, similar to utomilumab, urelumab and several other potential therapeutics [8, 27–30].