This is a single-center, open-label, investigator-initiated clinical trial. It aims to evaluate the safety and tolerability of RGL-270 in combination with a PD-1/PD-L1 inhibitor, to assess immunogenicity, preliminary efficacy, and exploratory biomarkers and to observe the safety and effectiveness of PD-1/PD-L1 inhibitor monotherapy in advanced NSCLC subjects through a real-world observational cohort.

1. Subjects capable of understanding/compliance with study procedures and voluntarily signing informed consent.
2. Age ≥18, any gender.
3. Histologically/cytologically confirmed NSCLC.

5.ECOG performance status 0 or 1.

6.Life expectancy ≥6 months.

7. Subject must have at least one measurable tumor lesion by RECIST 1.1 criteria at baseline prior to first-line treatment.

Note: Previously irradiated lesions not eligible as target lesions unless documented progression post-radiation.

8. Subjects with asymptomatic central nervous system (CNS) metastases (excluding meningeal or cerebrospinal membrane metastases) are allowed. For symptomatic CNS metastases, the condition must be stable after local treatment and no steroid or anticonvulsant treatment is required at least 7 days before enrollment (antiepileptic drugs are allowed).

9.Willing to provide sufficient fresh tumor tissue or archival specimens for genomic profiling and neoantigen analysis (fresh tissue preferred).

10.Willing to provide blood samples for immunogenicity/biomarker assessments at all timepoints. Pre-biopsy samples require no transfusion/blood products/G-CSF within 10 days.

11.Adequate organ function (no blood products/growth factors within 10 days prior to testing):

Hematology:

ANC ≥1.5×10⁹/L, LYM ≥0.5×10⁹/L, PLT ≥100×10⁹/L, Hb ≥90g/L

Biochemistry:

TBIL ≤1.5×ULN, ALT/AST ≤2.5×ULN, ALB ≥30g/L, Scr ≤1.5×ULN

Coagulation:

INR ≤1.5, APTT ≤1.5×ULN

Cardiac:

LVEF ≥50%

ECG:

QTcF <470 ms (Fridericia's correction: QTcF=QT/RR⁰·³³)

12.Women of childbearing potential (WOCBP): Negative pregnancy test within 7 days prior to treatment; non-lactating.

13.Women and male subjects with fertile partners must use contraception from consent until 90 days post-last treatment (see Appendix V).

Real-World Observational Cohort Addendum:

Exempt from tissue provision (Criterion 9) and immunogenicity blood sampling (Criterion 10). All other inclusion criteria apply.

Exclusion Criteria:

1. Histologically/cytologically confirmed small cell lung cancer (SCLC), mixed tumors with SCLC components, neuroendocrine tumors with large cell components, or sarcomatoid carcinoma.

2. Actionable driver mutations (e.g., EGFR/ALK) where targeted therapy is accessible per investigator assessment, except for patients refusing targeted treatment.

3. Prior radiotherapy within 5 years or history of immunotherapy/cancer vaccines (including but not limited to TILs, CAR-T, TCR-T, therapeutic cancer vaccines).

4. Live vaccines administered ≤28 days pre-screening or planned during study/within 90 days post-treatment (inactivated vaccines permitted).

5. Investigator-assessed contraindications for immunotherapy.

6. Active autoimmune diseases (exclusion: hypothyroidism from autoimmune thyroiditis requiring hormone replacement only).

7. Evidence of active tuberculosis within 1 year pre-screening, regardless of treatment.

8. History of interstitial lung disease (ILD), suspected active ILD on screening CT, or idiopathic pulmonary fibrosis/organizing pneumonia (e.g., BOOP/cryptogenic OP).

9. Severe active infection requiring IV antibiotics/antifungals/antivirals ≤28 days pre-screening or during screening.

10. Clinically uncontrolled effusions requiring drainage ≤14 days pre-screening (pleural/peritoneal/pericardial).

11. Hypersensitivity to study drug excipients or severe vaccine allergy history.

12. Other malignancies within 5 years (exceptions: cured cervical CIS, basal/squamous skin cancer, localized prostate cancer post-radical therapy, DCIS, papillary thyroid cancer).

13. Allogeneic organ or hematopoietic stem cell transplantation.

14. Congenital/acquired immunodeficiency (e.g., DiGeorge syndrome, T-/B-cell deficiencies, Wiskott-Aldrich, ataxia-telangiectasia, CVID) or HIV infection.

15. Active hepatitis B (defined as positive hepatitis B surface antigen [HBsAg] at screening AND HBV DNA ≥500 IU/mL or above the upper limit of normal [ULN] at the local institution), OR active hepatitis C (defined as positive hepatitis C antibody [HCV-Ab] at screening AND detectable HCV-RNA).

16. Uncontrolled or significant cardiovascular disease, including:

    Symptomatic congestive heart failure (NYHA Class III or IV) Myocardial infarction within 6 months prior to screening Unstable angina within 1 month prior to screening Clinically significant arrhythmias requiring therapeutic intervention Refractory hypertension despite adequate treatment (systolic BP ≥160 mmHg and/or diastolic BP ≥100 mmHg)

17. Any other condition deemed by the investigator to potentially compromise trial conduct or outcome interpretation, including but not limited to:

    Anticipated poor compliance with study procedures Comorbidities posing unacceptable safety risks Insufficient neoantigen burden for vaccine production (based on tumor sequencing analysis) Vaccine manufacturing failure

18. Subjects who experienced severe irAE during the run-in treatment period resulting in permanent discontinuation of PD-1/PD-L1 inhibitors.

19. If a subject experiences comprehensive disease progression during the introduction treatment but only has clinical deterioration, or if the intracranial lesion stabilizes after local treatment and the investigator assesses that medication can continue, they are allowed to continue participating in the study.