Haematology is a branch of medical science which studies blood and blood-forming tissue morphology. It includes the cellular composition of blood, the development of blood cells, the synthesis of hemoglobin, and all associated disorders. To help diagnosis and treatment control, hematological parameters are commonly used. It provides details about red and white blood cells and platelets, their relative proportions, general cell health, and the diseases caused by imbalances between them. Red blood cells have many important functions, but carrying carbon dioxide (CO2) and oxygen (O2) is their most important function. White blood cells are an important part of the immune defense system of the body, while platelets play an essential role in the coagulation of the blood. Finally, given the possible serious effects of COVID-19 on people with cancer, it is recommended that oncologists and hematologists support the timely application of COVID-19 to people with