This study is a multicenter, open-label, dose-finding/efficacy-expanding phase Ib/II clinical trial, which aims to observe and evaluate the tolerability, safety, pharmacokinetic characteristics and immunogenicity of HRS2398 combined with Adebrelimab injection in patients with advanced solid tumors, determine the RP2D, and preliminarily evaluate the efficacy of HRS2398 combined with Adebrelimab in patients with advanced solid tumors.

Inclusion Criteria:

1. Subjects are able to give voluntary informed consent, understand the study and are willing to follow and complete all the test procedures.
2. Age 18~75 years old.
3. Dose escalation phase: patients with clinically diagnosed or pathologically confirmed advanced solid tumors who have failed standard therapy (disease progression during or after treatment) or for whom no effective standard treatment regimen exists.
4. Dose Expansion and Efficacy Expansion Phase: Patients with advanced solid tumors who have received systemic immunotherapy and platinum-containing chemotherapy in the recurrent/metastatic settings.
5. At least one measurable lesion per RECIST v1.1 criteria.
6. ECOG PS score: 0-1.

Exclusion Criteria:

1. Patients with meningeal metastases; or with brain metastases that have not been treated with surgery or radiotherapy.
2. Cancerous ascites and pleural effusion with clinical symptoms, requiring puncture and drainage; or those who have received ascites, pleural effusion drainage within 14 days before the first dose.
3. Presence of any active, known autoimmune disease.