CD8+ T-cells are a type of immune cell that play a crucial role in the body's defense against infections and cancer. They are also known as cytotoxic T lymphocytes because they can directly kill infected or cancerous cells. These cells recognize specific antigens presented by infected or abnormal cells, allowing them to target and eliminate threats effectively. Once activated, CD8+ T-cells proliferate and can persist in the body as memory cells. This enables a faster and more robust immune response if the same pathogen is encountered again. Their function is essential for maintaining immune surveillance and protecting the body from various diseases.