Previous studies have shown that the HDAC6 inhibitor ACY-241 (citarinostat) can significantly reduce the expression of PD-L1 in MM cells, regulatory T cells, and pDCs, and the expression of PD-1 in CTLs, thereby downregulating the PD-1/PD-L1 signal and promoting anti-MM activity of CTLs and NKs (Figure 1D). Here, PDCD1 is linked to Miyoshi myopathy.