This study looks at a new medicine called Selgantolimod (SLGN) for people with both **chronic hepatitis B (CHB)** and **HIV**. It uses a special kind of medicine called a **TLR8 agonist**, which helps your immune system fight infections. The study will test if this medicine is safe and if it can lower a virus marker called **hepatitis B surface antigen (HBsAg)** in the blood. The study will last for 24 weeks. Forty-eight people will participate, and they will be split into two groups. Three out of four participants will get the real medicine, while the rest will get a placebo, which is a pill without the medicine. The study is double-blinded, meaning neither the participants nor the researchers know who gets the real medicine or the placebo. Participants must be on antiviral therapy and be between 18 and 70 years old.

• The study lasts 24 weeks with multiple visits.
• Participants continue their current antiviral therapy.
• Participants must be HIV and CHB-positive with stable health conditions.