• Subjects are able to comprehend the informed consent form, voluntarily participate, and sign the informed consent form.

• Subjects are ≥18 years old on the day of signing the informed consent form, with no gender restrictions.

• Histologically confirmed digestive system cancers.

• According to RECIST 1.1 criteria, there should be at least one measurable or evaluable lesion at baseline. If the subject has only one measurable or evaluable lesion at baseline, the lesion must not have been exposed to radiotherapy previously, or there must be evidence of significant progression after radiotherapy treatment completion.

• ECOG performance status of 0 or 1.

• Expected survival ≥3 months.

• Archived tumor tissue samples or freshly obtained tumor tissue samples are available.

• Female subjects of childbearing potential or male subjects with partners of childbearing potential agree to use highly effective contraception from 7 days before the first dose until 120 days after the last dose. Female subjects of childbearing potential must have a negative serum pregnancy test within 7 days before the first dose.

• Subjects have the ability and willingness to comply with the study protocol's visits, treatment plan, laboratory tests, and other study-related procedures.

• Within the first 7 days of initial dosing, subjects should have good organ function:

• HGB ≥ 80g/L, NEU ≥ 1.0\*10\^9/L, PLT ≥ 75\*10\^9/L, Cr≤1.5×ULN or CrCl≥50mL/min（Cockcroft-Gault method), TBiL ≤ 1.5×ULN, ALT and AST ≤3 ×ULN; for patients with liver metastasis ALT and AST ≤5 ×ULN, urine protein \<2+;,if urine protein ≥ 2+, 24 hour urinary protein quantity \<2g; INR, APTT, PT ≤ 1.5 ×ULN

• dMMR/MSI-H cancers resistant to PD1/PDL1 blockade. MSI status should be confirmed by PCR or NGS. If MSI status by PCR and NGS were not consistent, or no enough tissue were available for PCR or NGS testing, whether to enroll this patient should be determine by investigators.