Comparative efficacy and safety of immunotherapy in the first-line treatment of metastatic renal cell carcinoma: a systematic review and network meta-analysis - Liu, Zheran; Chen, Ye; Wei, Zhigong; He, Yan; Wang, Jingjing; Mu, Xiaoli; He, Ling; Li, Ruidan; Hu, Xiaolin; Peng, Xingchen (Annals of Palliative Medicine, 2021)