Humans have been using chile peppers for thousands of years. In fact, the most verifiable evidence shows chiles were domesticated as early as 6,000-6,100 years ago in both Peru and Mexico, though there's evidence to suggest they may have been used thousands of years earlier. Over the years, selective breeding and hybridization of these once wild plants has resulted in the over 50,000 chile pepper cultivars that are estimated to exist today.
As astounding as that is, the overwhelming majority of these peppers belong to only five different species in the Capsicum genus.
Capsicum annuum (Jalapenos, Cayennes, Serranos, Plobanos, Chili Peppers, Bell Peppers, and most other Sweet Peppers): Most of the peppers you have encountered most likely are strains of Capsicum annuum, considering it contains more pepper varieties than any other species and can be found in cultivation all over the world. The Latin name for the species is actually a mistake because the plant is not an annual.
Capsicum chinense (Aji Charapita, Bonnet Pepper, Habaneros, Ghost Pepper, Carolina Reaper, and all other super hot Peppers): This pepper species has a reputation for being quite hot, but despite their heat, they can be quite tasty with flavors ranging from citrus like to smoky.
Capsicum frutescens (Tabasco, Thai peppers, African Bird's Eye, malagueta pepper): This species has produced far fewer varieties and its peppers usually don’t get as big. This species is believed to have originated in South or Central America.
Capsicum baccatum (Aji Amarillo, Aji Omnicolor, and every Baccatum Pepper): Perhaps the most easily identifiable pepper species, pubescens pepper plants have deep purple flowers, large black seeds, and the stems and leaves are covered in small hairs. This is likely the first pepper to be domesticated, with its origins traced back to Peru before the Inca Empire.
Capsicum pubescens (Pubescens Pepper , Manzano and Locoto Pepper): Perhaps the most easily identifiable pepper species, because the pepper plants have deep purple flowers, large black seeds, and the stems and leaves are covered in small hairs. This is likely the first pepper to be domesticated, with its origins traced back to Peru before the Inca Empire. Despite originating so close to the equator, it is actually the most cold-tolerant pepper plant because it has been grown in high elevations in the Andes Mountains for thousands of years. If left to grow for many years, the plants can become huge, leading some to call it the tree pepper.