The immune system is a complex network of cells, tissues, organs, and molecules that protect the body from harmful microorganisms and cancer cells. The immune system is composed of two parts - non-specific (or innate) and specific (or acquired). The non-specific part is our first line of defense and works the same against all types of foreign bodies. The specific part, on the other hand, is more precise and adapts to specific threats, while at the same time remembering how to fight against the same threats in the future. A healthy immune system is extremely important for our well-being and health.