Additional Study Information: Almost 40,000 people get HIV in the U.S. each year and almost all occur via sexual contact, especially male-to-male contact. The number of new infections has decreased slightly each year, however, we need other HIV prevention tools, such as developing a greatly, effective HIV vaccine, to better reduce HIV infections. SCREENING AND EDUCATION: 1. Consent will be obtained prior to screening procedures 2. We will ask you to complete an electronic pre-screen questionnaire to help us determine your eligibility. 3. If eligible, we will ask you to attend a one-on-one educational visit (compensation: $20-25). If you are still interested in joining the study after reviewing the study with a staff member, we will ask about your medical history and draw blood to assess medical eligibility. 4. We will schedule a return visit to review the results of your blood tests. If eligible, we will ask you to review and sign a study-specific consent form and we will schedule you for the first study visit. STUDY PURPOSE AND PARTICIPANT DEMOGRAPHIC SOUGHT: 1. This study aka The Mosaico Study is a phase 3 HIV vaccine study to find out if the study vaccines can effectively prevent HIV among 18-60 year old and HIV-negative transgender people that have sex with cis-gender men and/or with transgender people or, cis-gender men that have sex with cis-gender men or, gender non-conforming people. 2. STUDY DESIGN & COMPENSATION The study consists of 13 visits over 30 months (about 1.5 hours per visit) including: 4 injection visits (placebo or vaccine); These are scheduled every 3 months throughout the first 12 months (2 x $100 + 2 x $150 = $500). 9 blood draw only visits (9 x $50 = $450). BONUSES: $50 for completing ALL 4 injection visits ($50 compensation given at visit 7.0 at month 12, if eligible). $50 at visit 12.0 at month 24 for completing the visit ($50 compensation given at visit 24.0). $100 at "Final Visit" for staying engaged with the study through the end ($100 compensation given at "Final