A conjunctive expression meaning 'even if' or 'whether ... or ...'; often used in patterns like 'AにしろBにしろ' to indicate that the following statement applies in either case.
雨にしろ雪にしろ、試合は中止になります。
Whether it's rain or snow, the match will be canceled.
失敗にしろ成功にしろ、経験から学ぶことが大切だ。
Whether you fail or succeed, it's important to learn from the experience.
彼にしろ私にしろ、まずは事情を確認する必要がある。
Whether it's him or me, we need to check the situation first.