PROJECT ABSTRACT This application is being submitted in response to the Notice of Special Interest (NOSI) identified as “NOT-CA- 24-028”. Cancer presents a significant burden in low- and middle-income countries (LMICs), with Africa facing a substantial share of this challenge. The Cancer-HIV Care Assistance and Monitoring using Peers Study (CHAMPS) aims to address the pressing public health issue of cancer among people living with HIV/AIDS (PLWH) by exploring the integration of cancer care into HIV care settings using peer support from expert clients in Botswana, a low-resource country grappling with both HIV/AIDS and cancer burdens. Aim 1 will investigates barriers and facilitators in cancer care cascade through a mixed-methods approach targeting PLWH co-diagnosed with cancer and healthcare providers from public oncology centers and co-located Infectious Disease Control Centers (IDCC). Aim 2 will assess the acceptability and feasibility of integrating expert client support for cancer care cascade within the IDCCs. Overall, the proposed research will: 1) inform the development of an R01 grant application for a randomized trial to investigate the effectiveness of integrating expert client support for cancer care among PLWH in Botswana and 2) provide mentorship and career development for Dr. Lillian Okui, MD, MPH, an early-stage low- and middle-income country investigator (ESLI) to become an independent investigator in cancer implementation science. Her mentorship team will be led by a highly experienced primary mentor (see Letter of Mentorship Support) and co-mentors who bring expertise in implementation science, clinical HIV and cancer care, epidemiology, and qualitative research. Her career development includes developing advanced research methodologies in design, and analytic techniques for cancer research, receiving training in implementation science, enhancing publication and presentation skills, expanding professional networks, and gaining skills in grant writing. Lastly, the proposed global cancer research is aligned with mission of the Botswana Ministry of Health, the LMIC institution, and the sponsoring institution, the University of Maryland School of Medicine and the University of Maryland Greenebaum Comprehensive Cancer Center (see Letters of Institutional Support).