광고에

in an advertisement

→ 광고

phrase Rare #31,641

in an advertisement 에 marks the advertisement as the place or context where something appears or happens.

KO: 광고에 새로운 제품이 나와요.

EN: A new product appears in the advertisement.

And give the ad a title, too.

I’m in an ad—a coffee commercial!

— 언터처블: 1%의 우정 (2011)

Just like it says in the ad?

— 델리카트슨 사람들 (1991)