text_1: 纳武利 尤 单抗 + 伊匹 单抗 组 患者 的 总 生存率 显著 高于 化疗 组 患者 , 但 不 符合 比例 风险 假设 .
  
text_2: the rate of overall survival was significantly higher among the patients who received nivolumab plus ipilimumab than among those who received chemotherapy , but the proportional @-@ hazards assumption was not met .
  