1. Male or female subjects greater than or equal to 18 years old；
2. Written informed consent obtained prior to any study-related procedure being performed;
3. Subjects with life expectancy ≥3 months;
4. Eastern Cooperative Oncology Group performance score 0 - 2;
5. Subjects must have histologically or cytologically confirmed advanced or metastatic solid tumor;
6. At least one measurable lesion based on RECIST version 1.1 .
You may not be if
1. History of other malignancies within 3 years before screening,unless radical non-melanoma skin cancer or basal cell carcinoma of the skin or carcinoma in the situ of the cervix;
2. Have central nervous system metastases;
3. Prior treatment with SHP2 inhibitor;
4. Have major surgery within 28 days prior to the first dose of GH21;
5. Left ventricular ejection fraction (LVEF) \<50 %;
6. Females who are pregnant or breastfeeding ;
7. Active hepatitis B virus (HBV) or hepatitis C virus (HCV) infection;
8. Conditions that the investigator considers inappropriate for participation in this clinical trial.
