Black tea is withered, rolled, oxidized and dried. There are two kinds of black teas in Yunnan: Dian Hong and Shai Hong.
Dian Hong is dried quickly with hot air, this process gives the leaves a light roast and the final tea has chocolatey or malty notes. This tea is at its best a couple of weeks after its production and can be properly enjoyed for two years.
Shai Hong is sun-dried, just like Pu-erh tea. It is not at its best right after production, months of aging will reveal its fragrance. Shai Hong tends to have a thicker mouthfeel than Dian Hong, the range of aromas it features is different. You could consider this tea a halfway between classical black tea and Pu-erh tea. It can be stored for over five years, its profile will change over time.
Different varietals are used when making Yunnan black tea. Dian Hong is often made of dedicated clonal varietals which will feature a specific fragrance, while Shai Hong is more often made of non-clonal varietals, typically the ones used to make Pu-erh tea.