He's going to New York on business next week.

Literal

Next-week he [topic-は] work [for-で] New York [to-に] goes.

仕事で ('for work / on business') uses で to mark the reason/purpose. Distinct from 仕事に行く ('go to work') — here 仕事で modifies 行く adverbially as 'by reason of work.' A compact everyday business travel phrase.