HDAC9 and non-small cell lung carcinoma: The first developed pan-HDAC inhibitor, vorinostat, was assessed in combination with pembrolizumab in patients with metastatic NSCLC in a phase I trial, showing a favorable safety profile with no dose-limiting toxicity and preliminary encouraging efficacy results with an ORR of 13% in the 30 evaluable patients, mainly pre-exposed to ICI [41].