This trial is a multi-center, open-label investigator-initiated clinical study (IIT) to evaluate the safety, pharmacokinetics, pharmacodynamics and effectiveness of WTX212A injection in the treatment of patients with unresectable or metastatic advanced solid tumors who failed in previous systematic therapy.

The study was divided into two phases: dose escalation and dose expansion

The study was divided into two phases: dose escalation and dose expansion Detailed Description: This trial is a multi-center, open-label investigator-initiated clinical study(llT)to evaluate the safety, pharmacokinetics, pharmacodynamics and effectiveness of WTX212A injection in the treatment of patients with unresectable or metastatic advanced solid tumors who failed in previous systematic therapy.

Inclusion Criteria:

• 1. Must signs an informed consent form, understands this study, is willing to follow and has the ability to complete all experimental procedures; 2. Aged 18 to 75 years old (including threshold); 3. Histopathology diagnosed unresectable or metastatic solid tumors who have failed systemic treatment or have no effective standard treatment, or who are unwilling to accept standard treatment or are not suitable for standard treatment; 4. ECOG≤1； 5. Expected life ≥ 3 months； 6. Male participants, their spouses, and female participants of childbearing age should agree to use a medically recognized effective contraceptive method from the signing of the informed consent form until 3 months after the last administration; 7. Women of childbearing age must have a negative pregnancy testing results within ≤ 7 days before the first trial drug administration.

Exclusion Criteria:

- 1. Other serious medical diseases, including but not limited to: uncontrolled diabetes, active peptic ulcer, active bleeding, etc., and people with uncontrollable or serious cardiovascular diseases, 2. Pleural and ascitic fluids with clinical symptoms and the need for repeated drainage; 3. Previous or recent history of pulmonary fibrosis, severe lung function damage caused by pneumoconiosis, radiation pneumonia, and drug-related pneumonia; 4. History of adverse events related to the use of IO drugs that require permanent cessation of IO treatment; 5. Known to have other malignant tumors, currently progressing or completing treatment at least once in the past 3 years.

6. Symptomatic central nervous system (CNS) metastasis confirmed by imaging or pathological examination and clinically unstable for at least 14 days prior to enrollment who require steroid treatment; 7. Hereditary bleeding tendencies or coagulation disorders, or a history of thrombosis, hemolysis, or hemorrhagic diseases; 8. Received significant surgical treatment or obvious traumatic injury within 28 days prior to the start of research treatment;