CD28 and neoplasm: Meanwhile, it has been reported that the autophagy inhibitor chloroquine inhibited human CD4+ T-cell activation and suppressed cytokine secretion, including tumor necrosis factor (TNF)-α, IFN-γ and interleukin (IL)-10 following anti-CD3/anti-CD28 activation [23], which may potentially inhibit the levels of PD-L1 expression in the adjacent tumor cells.