The finding that resveratrol upregulates PD-L1 expression by activating Wnt pathway is consistent with recent reports that dysfunction of Wnt pathway significantly altered PD-L1 expression in triple-negative breast cancer and suppression of Wnt signaling by IL-21 reduced PD-L1 expression in NSCLC cells (Castagnoli et al. 2019; Xue et al. 2019). Here, IL21 is linked to triple-negative breast carcinoma.