The aim of this randomized study is to compare the efficacy and safety of ondanstron weekly with every 3 weeks for the prevention of nausea and vomiting induced by chemotherapy combined with PD-1 blockade.
Age ≥ 18 years, no gender limit;
Pathologically or cytologically confirmed malignant solid tumors;
Scheduled to receive cisplatin-based chemotherapy combined with PD-1 blockade；
TPS > 1 %(PD-1);
Nausea or vomiting caused by reasons except for chemotherapy and PD-1 blockade;
Participants with other malignant tumors history previously;
Inability to read, comprehend, and finish questionnaires;
Allergic to the drugs included in this study.