Regorafenib with or without a programmed cell death protein 1 antibody as third‐line treatment for microsatellite stable metastatic colorectal cancer oleh Wen‐Zhuo He, Lei Wang, Chen‐Xi Yin, Jia‐Hong Yi, Ya‐Nan Jin, Chang Jiang, Gui‐Fang Guo, Liang‐Ping Xia