This is an open label, non-randomized bio-distribution trial, using a staggered approach:

Part 1: dosimetry and feasibility assessment of [89Zr]Zr-BI 770371 (arm B) PET / CT.

Part 2: assessment of tumor uptake [89Zr]Zr-BI 770371 (arm B) at various doses of BI 770371 treatment

Each patient will undergo 2 phases of PET imaging assessment, followed by study treatment with BI 770371 (arm B) and BI 754091 (anti PD-1).

Baseline assessment at Cycle 1

On-treatment assessment at Cycle 2 + study treatment

Relative change from baseline (Cycle 1, up to Day 7) of peak Standardized

Male or female aged ≥ 18 years (no upper limit of age) at the time of ICF signature

Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

Life expectancy of at least 3 months

For arm A: SIRPα polymorphism V1/V1

Patients with histologically or cytologically documented advanced/metastatic primary or recurrent HNSCC, melanoma, NSCLC who failed or are not eligible to standard therapy

Patients with at least one measurable lesion are allowed as per RECIST v1.1

Patient must have at least one PET imageable and evaluable tumor lesion with a diameter of at least 20 mm

Patients must agree to on-treatment tumor biopsies (optional for first 3 patients in Part 1)

Adequate biological parameters

Prior major treatment-related surgery completed at least 28 days before study drug administration

Interval of at least 28 days or 5 half-lives (whichever is shorter) since the last chemotherapy, approved immunotherapy, biological or investigational therapy, radiation or tyrosine kinase inhibitor (TKI) therapy must have elapsed before the first study drug administration(s) and all toxicities related to previous anticancer therapies have resolved to normal value or ≤ Grade 1 prior to the study treatment administration, except alopecia

Capable of understanding and complying with protocol requirements

Patients with symptomatic/active central nervous system (CNS) metastases; patients with previously treated brain metastases are eligible if there is no evidence of progression for at least 28 days before the first study treatment administration, as ascertained by clinical examination and brain imaging (MRI or CT) during the screening period

Other tumor location necessitating an urgent therapeutic intervention (e.g., palliative care, surgery or radiation therapy, such as spinal cord compression, other compressive mass, uncontrolled painful lesion, bone fracture)

Presence of other active invasive cancers other than the one treated in this trial within 5 years prior to screening (or less, pending discussion with sponsor), except appropriately treated basal cell carcinoma of the skin, or in situ carcinoma of uterine cervix, or other local tumors considered cured by local treatment

Patients with active autoimmune disease or a documented history of autoimmune disease, that requires systemic treatment (i.e. corticosteroids or immunosuppressive drugs); except patients with vitiligo, resolved childhood asthma/atopy, alopecia, or any chronic skin condition that does not require systemic therapy, patients with autoimmune-related hypothyroidism on a stable dose of thyroid replacement hormone and/or controlled Type 1 diabetes mellitus on a stable insulin regimen may be eligible

Known severe infusion related reactions to monoclonal antibodies (Grade >= 3 NCI-CTCAE v5.0) and patients removed from previous anti-PD-1 or anti-PD-L1 therapy because of a severe or life-threatening immune-related adverse event (irAE) (Grade >= 3 NCI-CTCAE v5.0);

Patients receiving systemic treatment with any immunosuppressive medication within one-week prior to treatment start with SIRPa antibody (BI 765063 or BI 770371) and ezabenlimb; steroids of max. 10 mg prednisolone equivalent per day are allowed, topical and inhaled steroids are not considered as immunosuppressive

Patients who have interstitial lung disease or active, non-infectious pneumonitis.

Patients with uncontrolled disease-related metabolic disorders (e.g., hypercalcemia, SIADH) or uncontrolled diabetes

Patients with uncontrolled congestive heart failure defined as New York Heart Association (NYHA) class III or IV, uncontrolled hypertension, unstable heart disease (e.g., coronary artery disease with unstable angina or myocardial infarction within 6 months before study treatment administration)

Patients with significant ECG abnormalities defined as any cardiac dysrhythmia (> Grade 2) (i.e., significant ventricular arrhythmia as persistent ventricular tachycardia and/or ventricular fibrillation; severe conduction disorders as atrio-ventricular block 2 and 3, sino-atrial block) or baseline QT/QTc interval >480 milliseconds (ms)

Patients with significant chronic liver disease (e.g., significant fibrosis, known cirrhosis) or active HBV or HCV infection; if HbsAg positive, an effective antiviral treatment to prevent hepatitis B reactivation is recommended

Patients with known Human Immunodeficiency Virus (HIV) infection or patients with an active infection requiring specific anti-infective therapy until all signs of infection have resolved, and this within 2 weeks prior to the first study treatment administration

Women who are breastfeeding. Women who are breastfeeding can be enrolled if they stop breastfeeding. In this case, the patient will not be permitted to resume breastfeeding even after discontinuation of study treatment.

Patients whose medical, psychological including alcohol or drug abuse, or surgical conditions are unstable and may affect the study completion and/or compliance and/or the ability to give informed consent.