This is an open-label, single-arm, Phase II investigator-initiated trial of antibody-drug conjugate combined with hypofractionated radiotherapy, PD-1/PD-L1 inhibitor sequential GM-CSF and IL-2 for treatment of advanced refractory solid tumors with HER-2 positive

Inclusion Criteria:

1. Aged 18 years and above;
2. Diagnosed with histologically or cytologically-confirmed, HER2-positive(IHC 1+, 2+ or 3+), standard treatment is ineffective (disease progresses after treatment) or locally advanced or metastatic malignant solid tumor patients who cannot tolerate standard therapy, cannot receive or do not have standard therapy;
3. ECOG(Eastern Cooperative Oncology Group) performance is 0-3;
4. Life expectancy greater than 3 months;
5. T lymphocyte absolute value ≥0.5 upper limit of normal (ULN), absolute neutrophil count(ANC)≥1.0 x 10(9)/L；serum aspartate transaminase (AST) and serum alanine transaminase (ALT) ≤3.0*ULN, or AST and ALT≤5*ULN with hepatic metastasis; Total serum creatinine ≤1.5*ULN；
6. Signed informed consent form；

Exclusion Criteria:

1. Current pregnancy or lactation；
2. History of other malignant tumors within 5 years prior to dose administration, expect for：malignancies that can be cured after treatment (including but not limited to adequately treated thyroid cancer, cervical carcinoma in situ, basal or squamous cell skin cancer);
3. Uncontrolled epilepsy, central nervous system diseases or mental illness;
4. Currently active clinically significant cardiovascular disease such as uncontrolled arrhythmia, congestive heart failure, or greater than or equal to Class 2 congestive heart failure as defined by the New York Heart Association Functional Classification, or history of myocardial infarction unstable angina, or acute coronary syndrome within 6 months prior to enrollment in the study;
5. Received allogeneic hematopoietic stem cell transplantation or solid organ transplantation;
6. Other serious, uncontrolled concomitant diseases that may affect protocol compliance or interpretation of outcomes, including active opportunistic infections or advanced (severe) infections, uncontrolled diabetes;
7. Allergic to any of the ingredients used in the study;
8. A history of immunodeficiency, including HIV positive or other acquired or congenital immunodeficiency disease, or a history of organ transplantation, or other immune-related disease requiring long-term oral hormone therapy;
9. Acute and chronic tuberculosis infection;
10. Other disorders with clinical significance according to the researcher's judgment.