However, as no standard treatment for chemo-resistant choriocarcinoma was recommended in current clinical practice, it should be noted that the patients in our institution were all treated with combined therapy of both individualized chemotherapeutic strategy and different PD-1 inhibitors (with or without sintilimab), which might not be conclusive in terms of the effectiveness of each treatment regimen. This evidence concerns the gene PDCD1 and choriocarcinoma.