Study of EOS-448 With Standard of Care and/or Investigational Therapies in Participants With Advanced Solid Tumors

Inclusion Criteria:

1. Provide a signed written informed consent for the trial
2. Have measurable disease, per RECIST v1.1
3. Have an Eastern Cooperative Oncology Group (ECOG) performance status of Grade 0 or 1.
4. Have adequate organ functions
5. Part 1A/1B/1C/1D/1E/1F : Have histologically or cytologically confirmed advanced or metastatic solid tumor for whom no standard treatment with survival benefit is available

Part 1G :

1. Have a histologically confirmed or cytologically confirmed newly diagnosed stage IV (M1a or M1b- AJCC 8th edition) non-squamous NSCLC OR squamous NSCLC.
2. Are eligible to receive anti-PD(L)1 therapy combined with chemotherapy in first line metastatic setting

Part 2 (lung cancer, H&N)

1. Have histologically or cytologically confirmed recurrent advanced or metastatic head and neck squamous cell carcinoma considered incurable by local therapies
2. PD-L1 status positive
3. Part 2 (melanoma) : progressed on treatment with an anti-PD-(L)1 monoclonal antibody (mAb)

Exclusion Criteria:

1. Have received any anti-cancer therapy within 4 weeks prior to the first dose
2. Have received a live vaccine within 30 days prior to the first dose
3. Have known primary CNS cancer.
4. Have known CNS metastases unless previously treated and well controlled for at least 1 month
5. Have concomitant second malignancies unless a complete remission was achieved at least 2 years before study entry
6. Have a history of Grade ≥ 2 pneumonitis, active autoimmune disease, or persistent immune-mediated toxicity caused by immune checkpoint inhibitor therapy of Grade ≥ 2
7. Have toxicity (except for alopecia) related to prior anti-cancer therapy and/or surgery unless the toxicity is either resolved, returned to baseline or Grade 1, or deemed irreversible.
8. Have uncontrolled or significant cardiovascular disease
9. Part 1 : major surgery within 5 weeks before initiating treatment
10. Part 1 : Have received prior radiotherapy within 2 weeks of start of study treatment
11. Part 2 (lung cancer, H&N) :Have confirmation that epidermal growth factor receptor (EGFR), anaplastic lymphoma kinase (ALK), reactive oxygen species (ROS1) or any other genomic aberration approved directed therapy is indicated as primary therapy.