According to Baidu Library, the soldiers who defended the frontier against the enemy and fought in Wan Li have not returned yet. The Long March Man Didn't Return is from the Tang Dynasty poet Wang Changling's Out of the Plug.
Full text: In Qin Dynasty, the bright moon was in the sky, the Han Dynasty closed its doors, the Long March did not return, the Dragon City soared, and Huma never taught Yinshan.