HIV stands for Human Immunodeficiency Virus. HIV attacks immune cells in the body, leading to AIDS if left untreated.
HCV stand for hepatitis C virus. HCV causes liver diseases, including fibrosis (mild scarring in the liver), cirrhosis (severe scarring in the liver), Hepatocellular carcinoma (liver cancer), and liver failure.
Both HIV and HCV are viruses and are transmitted in similar ways. You can have both HIV and HCV infection at the same time. HCV infection can be cured while HIV infection can not be cured but it is treatable.