PD1 Antibody Combined With mFOLFOX6 Neoadjuvant Therapy for Advanced Resectable Metastatic Colon Cancer

Inclusion Criteria:

* Signed the inform consent
* Age \>=18 years old, female and male
* Locally advanced or metastatic colorectal adenocarcinoma (including sig-ring cell carcinoma, mucinous adenocarcinoma, etc.) confirmed by pathology (histology or cytology)
* Enriched with proinflammatory panmacrophage subsets
* At least one measurable or evaluable lesion according to RECIST 1.1; Measurable lesions should not have received local treatment such as radiotherapy (Metastases can still be used as target lesions to evaluate efficacy after biopsy. Periintestinal lymph node imaging determines metastasis, allowing for a minimum diameter of ≥ 10mm, and can also be used as target lesions.)
* Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 1
* The life expectancy is ≥6 months；And according to the MDT in the hospital, only neoadjuvant chemotherapy is needed
* Hemoglobin content (HB) ≥ 90g/L; Absolute neutrophil count (ANC) ≥ 1.5 × 109/L;Platelet count (PLT) ≥ 100 × 109/L (did not use interleukin-11 or TPO within 14 days);White blood cell count (WBC) ≥ 4.0 × 109/L (no use of granulocyte stimulating factor within 14 days).
* Total serum bilirubin (TBIL) ≤ 1.5 times the upper limit of normal value (ULN); ALT and AST ≤ 2.5 × ULN;Cr ≤ 1.5 × ULN or creatinine clearance rate (CCr) ≥ 60ml/min, (Cockcroft Gault formula);Serum albumin ≥ 25 g/L (2.5 g/dL)
* For liver metastasis subjects, AST and ALT must be ≤ 5 x ULN, and white blood cells must be ≥ 4 × 109/L, platelets without blood transfusion ≥ 100 × 109/L, absolute neutrophil count (ANC) ≥ 1.5 without granulocyte stimulating factor treatment × 109/L, hemoglobin ≥ 90 g/L
* Doppler ultrasound evaluation: Left ventricular ejection fraction (LVEF) ≥ lower limit of normal value (50%).
* Adequate coagulation function, defined as international standardized ratio (INR) or prothrombin time (PT) ≤ 1.5 times ULN;

Exclusion Criteria:

* Allergy to any investigational drug or its excipients, or a history of severe allergies, or contraindications to investigational drugs;
* Having a history of autoimmune diseases or being in an active phase;
* Symptomatic/Asymptomatic Brain Metastasis
* CT indicates clear ulcerative lesions or fecal occult blood positive for three or more consecutive times, and clinical considerations suggest the presence of gastrointestinal bleeding
* Abnormal thyroid function or taking thyroxine tablets
* Previously received allogeneic bone marrow transplantation or organ transplantation;
* Congenital pulmonary fibrosis, drug-induced pneumonia, organized pneumonia, or CT confirmed active pneumonia;
* HIV positive, active hepatitis B or C, active pulmonary tuberculosis;