PDCD1 and cancer: Furthermore, the inhibition of LSD1 could elicit significant response to anti-PD-1 therapy in ICB-refractory mouse melanoma.510 Consistently, TCGA data analysis reveals an inverse correlation between LSD1 expression and CD8+ T-cell infiltration in various human cancers.510 In the same year, Qin et al.528 also found that combining LSD1 inhibitors with anti-PD-1 mAbs significantly suppressed tumor growth and pulmonary metastasis in mice bearing TNBC xenograft tumors, whereas anti-PD-1 mAbs alone failed to elicit an obvious anticancer effect.