Cadonilimab Combined With Regorafenib as A Third-line Treatment in Patients With MSS CRLM

Inclusion Criteria: * Age \> 18 years old and \< 75 years old; * ECOG Performance status score 0 or 1; * Histologically or cytologically confirmed adenocarcinoma of colon or rectum, with liver metastases, with or without extrahepatic metastases; * At least one measurable lesion as defined by RECIST version 1.1; * Progressed or be intolerant to prior systemic therapy including fluoropyrimidines, irinotecan, oxaliplatin, bevacizumab and/or cetuximab/panitumumab (if RAS/RAF-wild-type); * Known RAS and BRAF status; * Only patients with mismatch repair-proficient (pMMR)/microsatellite stable (MSS) status; * Adequate bone-marrow, liver, and renal function as assessed by the following laboratory requirements conducted within 7 days of starting to study treatment: Liver and renal function: Total bilirubin ≤ 1.5× ULNl; aspartate transaminase (AST), alanine transaminase (ALT) ≤ 5× ULN; Serum creatinine ≤ 1.5× ULN; Bone-marrow function: Neutrophil count ≥ 1.5×10\^9/L, Hemoglobin (Hb) ≥ 9.0 g/dL, Platelet count ≥ 100×10\^9/L; International normalised ratio (INR) and partial thromboplastin time (PTT) ≤1.5 × ULN. Subjects who are therapeutically treated with an agent such as warfarin or heparin will be allowed to participate provided that no prior evidence of an underlying abnormality in coagulation parameters exists. Close monitoring of at least weekly evaluations will be performed until INR and PTT are stable based on a pre-dose measurement as defined by the local standard of care； * …