It is an English figure of speech, indicating hope for good times after a long period of bad.

Recently, a friend used the phrase in describing what the series of donations by China of Sinovac vaccines would amount to in addressing the now long period of bad times wrought upon the Philippines by the Covid-19 pandemic. Those donations, now amounting to 1.5 million doses already delivered, have been programmed to reach an awesome amount of 2.5 million doses “at,” says my friend, “the end of the tunnel.”