Inclusion Criteria:  Histologically or cytologically confirmed diagnosis of an advanced, unresectable and/or metastatic or relapsed/refractory solid tumor.  Has accessible lesion(s), the number of accessible lesions depending on the arm into which the patient will be enrolled; either:  For patients being enrolled into an intratumoral (i.t.) containing arm (Arms A, C, D, F), at least two accessible lesions, one with a minimum lesion diameter for injection of BI 1831169, one which is amenable to biopsy. Lesions must either be easily accessible, or, if not easily accessible, patient must be willing to undergo repeat procedures (e.g., imaging guided procedures) for both biopsies and injections of BI 1831169. or For patients being enrolled into an intravenous (i.v.) only arm (Arms B and E), at least one accessible lesion which is amenable to biopsy. The lesion must either be easily accessible, or, if not easily accessible, patient must be willing to undergo repeat procedures (e.g., imaging guided procedures) for biopsies. Has failed conventional treatment or for whom no therapy of proven efficacy exists or who is not eligible for established treatment options. Patient must have exhausted available treatment options known to prolong survival for their disease. Medically fit and willing to undergo all mandatory trial procedures. Eastern Cooperative Oncology Group (ECOG) score of 0 or 1. Adequate organ function or bone marrow reserve at screening. All toxicities related to previous anti-cancer therapies (including Immune-related Adverse Event (irAEs)) have resolved to ≤ Common Terminology Criteria for Adverse Events (CTCAE) grade 1 prior to the start of trial treatment (except for alopecia, xerostomia and immunotherapy related endocrinopathies which may be included if clinically stable on hormone supplements or antidiabetic drugs as per Investigator judgement) and others per Investigator judgement. Patients ≥ 18 years of age or over the legal age of consent in countries where that is greater than 18 years at the time of signature of the Informed Consent Form (ICF).  Further inclusion criteria apply.  Exclusion Criteria:  Major surgery (major according to the Investigator's assessment) performed within 4 weeks prior to start of study treatment. Radiotherapy within 4 weeks prior to the start of study treatment, except in case of a brief course of palliative radiotherapy (e.g., for analgesic purpose or for lytic lesions at risk of fracture) which can then be completed within two weeks prior to start of study treatment.  Note: No radiation must have been given to any lesions planned to be injected and/or biopsied within 6 months of start of treatment.  Active hepatitis B or C infection e.g., Hepatitis B surface antigen (HBsAg) positive, or hepatitis C (HCV) antibody (anti-HCV) positive (except if HCV-Ribonucleic Acid (RNA) negative), which in the opinion of the Investigator may interfere with participation in the trial. Patients with history of human immunodeficiency virus (HIV) infection meeting certain criteria. Presence of brain metastases (as per cranial imaging Magnetic Resonance Imaging (MRI) or Computerized Tomography (CT), performed at most 6 weeks prior to first treatment). Active infection requiring systemic therapy (antibacterial, antiviral, antiparasitic or antifungal therapy) at the start of treatment in the trial.  Further exclusion criteria apply.