Radiotherapy Combined With Tislelizumab and Irinotecan in MSS/pMMR Recurrence and Metastatic Colorectal Cancer

Explore the efficacy of radiotherapy combined with Tislelizumab and irinotecan in MSS/pMMR inoperable recurrent and metastatic colorectal cancer patients; To evaluate the safety and tolerability of radiotherapy combined with Tislelizumab and irinotecan in MSS/pMMR inoperable recurrent and metastatic colorectal cancer; To evaluate the radiosensitization effects of Tslelizumab and irinotecan;