The Primary Objective of This Study to Evaluate the Safety and Tolerability of IBI334 and Determine the Maximum Tolerated Dose (MTD) and the Recommended Phase 2 Dose (RP2D)and Anti Tumor Activity of IBI334.

A Phase I/II Study of IBI334 in Subjects With Unresectable, Locally Advanced or Metastatic Solid Tumors

This is open-label, multicenter, Phase I/II study is designed to evaluate the Safety and tolerability and Efficacy of IBI334 Monotherapy in participants with advanced solid tumors.

Inclusion Criteria：

1. Subjects with the ability to understand and give written informed consent for participation in this trial, including all evaluations and procedures as specified by this protocol;
2. Male or female subjects ≥ 18 years old;
3. Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 or 1;
4. Anticipated life expectancy of ≥ 12 weeks;
5. At least 1 evaluable lesion per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1with Phase Ia ;At least 1 measurable lesion per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 with Phase Ib+II；

Exclusion Criteria：

1. Participate in any other interventional clinical research except observational (non-interventional) study or in the follow-up phase of the interventional study;
2. Received live vaccines within 4 weeks prior to first dose of the study drug or plan on receiving any live vaccine during the study;
3. History of immunodeficiency disease, including congenital or acquired immunodeficiency diseases;
4. Severe allergic or hypersensitive to other EGFR or B7H3 antibodies or any ingredients of IBI334;
5. Plan to receive other antitumor therapy during the study excluding palliative radiotherapy for the purpose of symptom (like pain) relief, which must not affect tumor assessment throughout the study;