Various ongoing clinical trials are also exploring the combined treatment of HDAC inhibitors with PD-1 monoclonal antibodies in the treatment of HL, DLBCL, FL, PTCL, CTCL, AITL, ENKT, and HLH secondary to ENKT (Table 4). This evidence concerns the gene PDCD1 and mature T-cell and NK-cell non-Hodgkin lymphoma.