expression
in contrast; on the other hand; while
Used to contrast two things, often with a negative or surprising second clause. The pattern is typically A に引き替えて B, where B is notably different from A.
兄は真面目だ。それに引き替えて、弟はいつも遊んでばかりだ。
The older brother is serious. In contrast, the younger brother is always playing around.
去年の夏は涼しかった。それに引き替えて、今年は猛暑だ。
Last summer was cool. In contrast, this year is extremely hot.
Combination of それ (that) + に (particle) + 引き替える (to exchange, to replace) in the て-form. Literally 'exchanging that for this', it developed into a contrastive conjunction.