PDCD1 and cancer: Interestingly, two combinations (anti-PD-1 antibody combined with regorafenib plus chidamide-k30 and anti-PD-1 antibody combined with cabozantinib plus chidamide-k30) showed good OS, even with a moderate ORR (~30 to 40%); this finding indicated that these two triple regimens might potently activate the immune system to inhibit cancer cell growth and avoid relapse, as shown in Table 2.