Chronic Lymphoblastic Leukemia (CLL) is a type of cancer that affects the blood and bone marrow. It primarily involves the overproduction of abnormal lymphocytes, a type of white blood cell that plays a crucial role in the immune system. CLL typically progresses slowly and is more common in older adults, although it can occur at any age. Symptoms of CLL may include fatigue, swollen lymph nodes, and frequent infections. Diagnosis is usually made through blood tests and bone marrow examinations. Treatment options may involve chemotherapy, targeted therapies, or immunotherapy to help manage the disease and improve quality of life.