This is an open-label, multi-cohort, multicenter Phase Ib/II clinical study designed to evaluate the safety, tolerability, and efficacy of SYS6090 injection in combination with chemotherapy or chemotherapy and bevacizumab or SYS6010 (an EGFR ADC) in participants with advanced lung cancer.

Inclusion Criteria:

1. Voluntarily signed written informed consent.
2. Age 18 to 75 years at the time of informed consent, with no restriction on sex.
3. Histologically or cytologically confirmed unresectable locally advanced (stage IIIB/IIIC) or metastatic (stage IV) non-small cell lung cancer (NSCLC) according to the AJCC/UICC Cancer Staging System, 8th edition, or extensive-stage small cell lung cancer (SCLC), not amenable to curative surgical resection or definitive chemoradiotherapy.
4. At least one measurable lesion according to RECIST v1.1.
5. Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1.
6. Estimated life expectancy of at least 3 months.
7. Has protocol-defined adequate organ and bone marrow function.

Exclusion Criteria:

1. Use of systemic corticosteroids or other immunosuppressive therapies within 14 days prior to the first dose of study treatment, except for physiologic replacement doses or permitted local, inhaled, or prophylactic use.
2. Unresolved > Grade 1 toxicities related to prior anticancer therapy (except for toxicities judged by the investigator to pose no safety risk).
3. For Cohorts 5A and 5B: prior permanent discontinuation of EGFR-targeted therapy due to dermatologic toxicity, or presence of dermatologic diseases requiring systemic treatment.
4. Known active central nervous system metastases or leptomeningeal metastases, except for stable and adequately treated brain metastases without the need for ongoing corticosteroids or antiepileptic therapy.
5. History of interstitial lung disease or non-infectious pneumonitis requiring corticosteroid treatment; current ILD or non-infectious pneumonitis; or inability to exclude these conditions at screening.
6. History of severe cardiovascular or cerebrovascular disease.
7. Active or recurrent autoimmune disease requiring systemic treatment, except for clinically stable or well-controlled conditions as specified in the protocol.
8. Prior immunotherapy associated with severe immune-related adverse events (≥ Grade 3) or immune-related myocarditis (≥ Grade 2), excluding stable immune-related endocrine disorders.
9. Clinically significant bleeding events (≥ Grade 2 according to NCI-CTCAE v6.0) within 4 weeks prior to the first dose of study treatment.
10. Arterial or venous thromboembolic events within 6 months prior to the first dose of study treatment, unless judged by the investigator to be clinically stable and low risk.
11. Presence of ascites or pleural effusion requiring drainage within 14 days prior to the first dose.
12. Known hypersensitivity to any component of the study treatment, history of severe hypersensitivity or infusion-related reactions to protein-based therapies, or poorly controlled asthma.
13. Untreated spinal cord compression.
14. History of other malignancies within 2 years prior to enrollment or concurrent active malignancy, except for cured localized tumors. -