Acquired immunodeficiency syndrome (AIDS) is a serious condition caused by the human immunodeficiency virus (HIV). This virus attacks the body's immune system, specifically the CD4 cells, making it difficult for the body to fight off infections and diseases. Without treatment, HIV can progress to AIDS, which is the final stage of the infection. AIDS is characterized by the occurrence of certain opportunistic infections or cancers that arise due to the weakened immune system. While there is no cure for AIDS, antiretroviral therapy (ART) can help manage the virus, allowing individuals to live longer, healthier lives.