The National Institutes of Health (NIH) is offering a funding opportunity titled "Development and Testing of Novel Interventions to improve HIV Prevention, Treatment, and Program Implementation for People Who Use Drugs." This initiative aims to support formative research and pilot-testing of innovative interventions that address HIV prevention and treatment specifically for populations affected by substance use. The focus is on developing strategies that are feasible, acceptable, and safe, utilizing a combination of behavioral, social, and structural approaches to enhance health outcomes in marginalized communities. Applicants can seek funding of up to $450,000 over a maximum of three years, with proposals due by January 7, 2025. For further information, interested parties can contact the NIH OER Webmaster at grantsinfo@nih.gov or visit the funding announcement page at http://grants.nih.gov/grants/guide/pa-files/PA-21-205.html.