Trendsetting is the adjective: it describes a person, thing, company or piece of work that starts a fashion others then follow. So a trendsetter is the person, and 'trendsetting' is what you call them or their work — 'a trendsetting designer', 'her trendsetting album', 'a trendsetting design'. It carries praise: it says this came first and changed what came after. Two useful habits of the word. First, it very often sits right in front of a noun ('a trendsetting show'); it is much less common after 'be' — people write 'the album was trendsetting', and it is understood, but 'a trendsetting album' sounds more natural. Second, it is a favourite of advertising and journalism, so it can feel a little inflated; when a shop calls itself trendsetting, treat it as a sales word. Used honestly, it is usually said looking backwards — we can only really see that something was trendsetting after other people copied it.

引領潮流的、開風氣之先的（形容詞，用來修飾人、作品或品牌）