A Study to Learn About the Medicine Called PF-08653944 in People With and Without Reduced Liver Function

Inclusion Criteria: * Adults 18 to 75 years of age, male or female. * BMI ≥21 kg/m² and body weight \>50 kg at screening. * Group 1 (without hepatic impairment): * No known or suspected hepatic impairment. * Normal liver function tests (ALT, AST, bilirubin, albumin, PT within normal limits, with protocol-specified exceptions such as Gilbert's syndrome). * Groups 2-4 (with hepatic impairment): * Stable hepatic impairment classified as Child-Pugh Class A (mild), B (moderate), or C (severe). * No clinically significant worsening of hepatic status within 28 days prior to screening. * Women of childbearing potential must not be pregnant or breastfeeding and must agree to use highly effective contraception. Exclusion Criteria: * Clinically significant medical or psychiatric conditions, including recent or active suicidal ideation or behavior. * Use of GLP-1 receptor agonists within 90 days (or 5 half-lives) prior to dosing. * Participation in another investigational study or receipt of an investigational product within 30 days (or 5 half-lives) prior to dosing. * For hepatic-impairment groups only: * Hepatic carcinoma, hepatorenal syndrome, or limited life expectancy. * Clinically active Grade 3 or 4 hepatic encephalopathy. * Severe uncontrolled ascites, recent gastrointestinal bleeding, or history of solid organ transplant.