に関(かか)わるTo relate to, To have to do with, Concerning, Depends on

Both patterns relate to a topic, but differ in meaning, tone, and grammatical usage. について means 'about (A)' or 'concerning (A)' and attaches to verb phrases, e.g. スポーツについて話す ('Talk about sports'), while にかかわる is more formal and attaches to nouns, typically describing a more serious or consequential relationship, such as one involving life, health, or major repercussions, e.g. 命にかかわる問題 ('A life-threatening issue').

Both follow nouns to express the idea of being related to or having to do with something, but they differ in nuance and structure. に関する・に関して attaches to a noun to mean 'about (A)' or 'concerning (A)', e.g. 歴史に関する本 ('a book about history'). にかかわる also connects to nouns but often implies a more serious or impactful relationship, e.g. 命にかかわる問題 ('a life-threatening issue').

While both にかかわる and において・における describe relationships with nouns, their meanings differ. にかかわる expresses significant relevance or impact, often with serious subjects, e.g. '命にかかわる' ('a matter of life'). において・における simply marks context without implying influence, e.g. '歴史において重要な事件' ('an important event in history').

次第 emphasizes timing or sequencing, used to express that one action is a condition for the next, which will follow immediately. For example, 準備ができ次第出発します ('As soon as preparations are done, we'll depart'). にかかわる focuses on relevance or importance, describing how something affects or relates to another matter. For example, 命にかかわる問題 ('a matter of life').