WeChat KOLs (key opinion leaders) are popular accounts that already have a large number of subscribers. These can be individuals or media organizations that have operate a WeChat Official Account. Brands can search KOLs on WeChat or through marketing agencies. The cooperation model usually requires you to prepare or confirm the content with KOLs who then publish it on their WeChat Official Accounts to promote your brand.
In recent years KOLs have become one of the primary drivers for success on WeChat for business.
In terms of WeChat promotion strategies, this is likely the most commonly used. However, as Chinese consumers have been bombarded with KOL marketing for the last few years it will likely begin to drop in effectiveness.