An expression meaning that, whether you cry or laugh (i.e., whatever the outcome), nothing can be changed — used when something is imminent or drawing to a close.
明日は試験だ。泣いても笑っても今日が最後の勉強日だ。
The exam is tomorrow. Whether you cry or laugh, today is the last day to study.
プロジェクトの締切は来週で、泣いても笑ってもあと一週間しかない。
The project deadline is next week; whether you like it or not, there's only one week left.
引っ越しの日は決まっているから、泣いても笑っても準備を終わらせよう。
The moving date is set, so whether you cry or laugh, finish the preparations.