冬去春来 is a four-character idiom (成语) that literally means 'winter goes, spring comes'. It describes the natural cycle of seasons and is often used figuratively to express that after a period of hardship or difficulty, better times will arrive — much like the English saying 'after winter comes spring'. You can use it in both literal seasonal contexts and metaphorical ones about life, business, or relationships. It's a common set phrase in written and formal speech.