HIV and AIDS pose great challenges to the health system as well as to society in Ethiopia, especially due to the secondary diseases with opportunistic infections, above all tuberculosis. Projects in this area dealt, for example, with intestinal parasites in HIV patients, with the effects of the COVID-19 pandemic on the quality of care for HIV and TB patients, and with various other concomitant infections. Surveys on therapy control and the investigation of therapy failure in connection with HIV resistance were also carried out. For the purpose of the scientific collection and evaluation of these data, there is a close cooperation between the colleagues of the HITM and the HIV outpatient clinic of the department in Düsseldorf, which looks after more than 5,000 HIV patients. The regular intake of the combined antiretroviral therapy (cART) is crucial here, as well as the follow-up examinations and the timely detection of therapy failure.