There is no latent period for melanoma. The incubation period is usually referred to as an infectious disease, and is the entire process from the onset and development of the disease until the manifestation of clinical symptoms, called the latent period. Melanoma itself evolves gradually from a pigmented nevus, and it usually takes about 2 years for a nevus to grow and change its nature to become a melanoma, so there is no latent period for melanoma. Melanoma is a type of malignant tumor of melanin origin. Melanocytes exist in the skin of ordinary people and are mainly located in the epidermal hair growth layer.