PDCD1 and neoplasm: As shown in Fig. 8C, at the endpoint (PG-D23), the tumor volume of the vehicle group was 2921.70 ± 168.78 mm3, and the tumor volumes of the high-dose ZGGS15, low-dose ZGGS15, anti-PD-1 antibody, and the combination of high-dose ZGGS15 plus anti-PD-1 antibody were 883.57 ± 281.26 mm3, 988.33 ± 412.03 mm3, 760.49 ± 198.41 mm3, and 181.10 ± 91.28 mm3, respectively.