: - Adult participants ≥18 years and ≤80 years of age at Visit 1. - Signed and dated written informed consent in accordance with International Council for Harmonisation-Good Clinical Practice (ICH-GCP) and local legislation prior to participation in the trial. - Male and female participants. Women of childbearing potential must be willing and able to use a highly effective method of contraception per ICH M3 (R2) that results in a low failure rate (i.e. <1% per year when used consistently and correctly) for the duration of the trial until at least 14 days after drug administration. Throughout the trial and for a period of at least 14 days after investigational medicinal product (IMP) administration, male participants with sexual partners who are women of child-bearing potential must use condoms or practice complete abstinence. - Body mass index (BMI) of 18.5-42.0 kg/m² (inclusive) at Visit 1. Inclusion criteria Cohort 4 (participants with normal hepatic function) - Clinically healthy based on medical history, physical examination, vital signs, Electrocardiogram (ECG), and laboratory tests at Visit 1. Inclusion criteria Cohorts 1, 2 and 3 (participants with hepatic impairment) - Hepatic impairment that meets the criteria for Child-Pugh classes A (Cohort 1), B (Cohort 2), or C (Cohort 3). - Hepatic decompensation therapies (e.g., diuretics for ascites, lactulose for hepatic encephalopathy, nonselective betablockers for portal hypertension) need to comply with following requirements: - No new initiation or permanent discontinuation is permitted within 3 months prior to Visit 1. - Major dose modifications (>50% change from baseline) within 4 weeks prior to Visit 1 are exclusionary. - Minor titrations consistent with standard clinical management are permitted, provided the investigator confirms that the patient's underlying condition is clinically controlled. Cases involving fluctuating hepatic directed regimens may be included only if both the investigator and the sponsor agree that the patient's clinical condition is controlled and suitable for trial participation.

: - Participation in another clinical trial within 30 days or 5 half-lives of the investigational drug (whichever is longer) prior Visit 2. - Known hypersensitivity to BI 3000202 or any of its excipients. - Any documented active or suspected malignancy or history of malignancy within 5 years prior to Visit 1 (except appropriately treated basal cell carcinoma or squamous cell carcinoma of the skin, or in situ carcinoma of uterine cervix (treated >3 years); patients with a remote history of malignancy (≥5 years prior) may be considered and must be discussed with sponsor on a case-by-case basis. - Have received stem cell transplantation. - Have received live or attenuated vaccination within 8 weeks prior to Visit 2. - Have received Bacillus Calmette-Guérin (BCG) vaccines ≤1 year prior to Visit 2. - Presence of relevant chronic or acute infections, including active systemic infection requiring antibiotics within 6 weeks prior to Visit 2. - Active or latent tuberculosis (TB). - Participants with active TB will always be excluded. - Participants with latent TB will be excluded if tested positive for Interferon-gamma release assay (IGRA) (QuantiFERON®-TB Gold Plus or T-SPOT®.TB) at Visit 1, not having completed appropriate treatment per local practice/guidelines for TB within the past 3 years and at least 1 month before Visit 2. - Participants with indeterminate QuantiFERON®-TB Gold Plus or borderline or invalid T-SPOT®. TB may be retested with IGRA (once) and will be excluded if retesting is inconclusive or positive. - Under exceptional circumstances and only after discussion with the sponsor, purified protein derivative (PPD) skin test can be performed if IGRA is not available. A PPD ≥10 mm (≥5 mm if receiving ≥15 mg/day prednisone or other immunosuppressant) is considered positive. Participants with a positive PPD are excluded unless they have completed treatment as above. Further exclusion criteria apply.