A Study to Evaluate Safety, PK and Efficacy of GH55 in Combination With GH21 in Patients With Solid Tumors

Inclusion Criteria: * 1\. Aged 18-80 years (inclusive), regardless of gender. * 2\. Histologically or cytologically confirmed locally advanced or metastatic solid tumor with aberrantly activated MAPK signaling pathway (RAS/RAF/MEK/ERK). * 3\. Failed standard treatment, has no standard treatment options, refuses standard treatment, or is not eligible for standard treatment at the current stage. * 4\. Has at least one measurable tumor lesion per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. * 5\. Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1. * 6\. Estimated survival time ≥ 3 months. * 7\. Essential organ function is basically normal, with screening laboratory results meeting the following criteria: * Hematological system (no blood transfusion or hematopoietic stimulants within 14 days) * Absolute Neutrophil Count (ANC) ≥1.5×109/L * Platelet (PLT) ≥75×109/L * Hemoglobin (Hb) ≥90g/L * Liver function * Albumin (ALB) ≥3.0g/dL * Total Bilirubin (TBIL) ≤1.5×Upper Limit of Normal (ULN); \<br/\>For patients with --Gilbert syndrome: ≤3×ULN * Alanine Aminotransferase (ALT) ≤2.5×ULN; \<br/\>For patients with liver metastasis or liver cancer: ≤5×ULN * Aspartate Aminotransferase (AST) ≤2.5×ULN; \<br/\>For patients with liver metastasis or liver cancer: ≤5×ULN * Renal function * Creatinine (Cr) ≤1.5×ULN * Creatinine Clearance (Ccr) ≥50ml/min (calculated by Cockcroft-Gault formula) * Coagulation function * Activated P…