The short answer is that to traffick [in] is the verb form of the noun traffic. This has around a dozen meanings, but basically it means the movement of something over some kind of route or in some area.

What is the difference between traffic and traffick?

As verbs the difference between traffick and traffic

is that traffick is (traffic) while traffic is to pass goods and commodities from one person to another for an equivalent in goods or money; to buy or sell goods; to barter; to trade.

What does it mean to traffick?

/ˈtræf.ɪ.kɪŋ/ the act of buying or selling goods illegally: arms/drug trafficking. He was wanted on charges of trafficking in stolen property.