Attending that industry summit was a career-changing experience that made her decide to switch to the tech field.

career-changing 是由名词 career（职业）和动词 change（改变）加上连字符和现在分词后缀 -ing 构成的复合形容词。career 指"职业、事业"，change 指"改变"，career-changing 合起来表示"改变职业方向的"或"职业生涯转折性的"。