This study is enrolling patients with uncontrolled high blood pressure. This study will see if a medication called Zilebesiran can help lower blood pressure. Zilebesiran is an investigational medication meaning it is not approved for commercial use by the Food and Drug Administration (FDA) but it is approved for use in this study. This is a randomized study meaning if you are eligible, you will be assigned by chance, like the flip of a coin to receive Zilebesiran or placebo. Placebo will look like the study medication but will not contain any active ingredients. You and the study team will not know if you are taking Zilebesiran or placebo, both of which are given as an injection under the skin every six months. This study will last between 2.5 and 5 years and include 10-14 visits. Study related procedures include physical exams, medical history including medications, vital signs, blood and urine collection. and electrocardiogram (ECG - a recording of your heart's electrical activity)