A Study in People With Advanced Cancer to Test How Well Different Doses of BI 770371 Alone or in Combination With Ezabenlimab Are Tolerated

Inclusion Criteria: * Signed and dated written informed consent form (ICF) in accordance with International Council for Harmonisation-Good Clinical Practice (ICH-GCP) and local legislation prior to admission to the trial * Patients ≥18 years of age and over the legal age of consent as required by local legislation at the time of signature of the ICF * Presence of at least one measurable lesion according to Response Evaluation Criteria In Solid Tumours (RECIST) v1.1 * Eastern Cooperative Oncology Group (ECOG) Score: 0 to 1 * Life expectancy ≥3 months at the start of treatment in the opinion of the Investigator. * Patients with a confirmed diagnosis of advanced, unresectable, and/or metastatic solid tumours (any type) * Patients who have failed conventional treatment or for whom no therapy of proven efficacy exists or who are not eligible for established treatment options (including anti-Programmed Cell Death 1 (PD-1) or anti-Programmed Death-Ligand 1 (PD-L1) therapies, if relevant). Patients must have exhausted available treatment options known to prolong survival for their disease * All toxicities related to previous anti-cancer therapies have resolved ≤ Common Terminology Criteria for Adverse Events (CTCAE) Grade 1 prior to trial treatment administration (except for alopecia, peripheral neuropathy and endocrinopathies considered irreversible \[like hypothyroidism\], and amenorrhea/menstrual disorders which can be any grade) Further inclusion criteria apply Exclusion Criteria: * Major surgery (major according to the Investigator's assessment) performed within 12 weeks prior to randomisation or planned within 12 months after screening, e.g. hip replacement * Presence of active invasive cancers other than the one treated in this trial within 5 years prior to screening, with the exception of appropriately treated basal-cell carcinoma of the skin, in situ carcinoma of the uterine cervix, or other local tumours considered cured by local treatment * Untreated brain metastasis(es) that may be considered active. Patients with previously treated brain metastases may participate provided they are stable (i.e., without evidence of Progressive Disease (PD) by imaging for at least 4 weeks prior to the first dose of trial treatment, and any neurologic symptoms have returned to baseline), and there is no evidence of new or enlarging brain metastases * Radiotherapy within 4 weeks prior to randomisation except as follows: * Palliative radiotherapy to regions other than the chest is allowed if completed at least 2 weeks prior to randomisation * Single dose palliative radiotherapy for symptomatic metastasis within 2 weeks prior to randomisation may be allowed but must be discussed with the Sponsor * Patients who must or wish to continue the intake of restricted medications or any drug considered likely to interfere with the safe conduct of the trial * History of pneumonitis within the last 5 years or Interstitial lung disease * Known history of allergy to any trial drug, or any excipients of the trial drug(s) * History of severe hypersensitivity reactions and/or severe infusion related reactions (Grade ≥ 3 National Cancer Institute (NCI) CTCAE v5.0) to other Monoclonal Antibodies (mAbs) Further exclusion criteria apply