This is a Phase 1, open-label, parallel-group study to evaluate the pharmacokinetics of GSK3228836 in participants with Child-Pugh B (CP-B) cirrhosis (moderate hepatic impairment), Child-Pugh A (CP-A) cirrhosis (mild hepatic impairment) and participants with normal hepatic function as healthy control.

Inclusion Criteria:

• Body weight >50 Kilogram (kg) and body mass index (BMI) within the range 19 to 40 Kilogram per square meters (kg/m2) (inclusive)
• Capable of giving signed informed consent.
• Child-Pugh B cirrhosis (moderate hepatic impairment; Part 1) or Child-Pugh A cirrhosis (mild hepatic impairment; Part 2) or a healthy control participant based on a medical evaluation including medical history, physical examination (PE), laboratory tests.

Exclusion Criteria:

• Diagnosed or suspected hepatocellular carcinoma.
• History of malignancy within the past 5 years except for cancers that are cured by surgical resection (e.g., skin cancer).
• History of vasculitis or presence of symptoms and signs of potential vasculitis or history/presence of other diseases that may be associated with vasculitis condition.
• Unstable cardiac function or high blood pressure that is not controlled (based on the investigator's discretion).
• Any other medical condition which, in the judgment of the investigator and Medical Monitor, could jeopardize the integrity of the data derived from that participant or the safety of the participant.
• Participants who have taken or are currently taking any therapies not allowed by the protocol.
• A positive test for human immunodeficiency virus (HIV) antibody.
• History of sensitivity to GSK3228836 or components thereof or a history of drug or other allergy that, in the opinion of the investigator or Medical Monitor, contraindicates their participation.

IPD for this study will be made available via the Clinical Study Data Request site.

IPD will be made available within 6 months of publishing the results of the primary endpoints, key secondary endpoints and safety data of the study.

Access is provided after a research proposal is submitted and has received approval from the Independent Review Panel and after a Data Sharing Agreement is in place. Access is provided for an initial period of 12 months but an extension can be granted, when justified, for up to another 12 months.