Ning Cai, who pioneered the field of network coding, passed away on May 25, 2023 at the age of 75. His profound contributions, ranging from quantum information theory to network information theory, have a long-lasting influence on generations of researchers. Prof. Cai's contributions to network coding have received numerous recognitions, including the 2005 IEEE Information Theory Society Paper Award for the paper “Linear network coding” and the 2018 ACM SIGMOBILE Test-of-Time Paper Award for the paper "Network information flow.” He also received the 2016 IEEE Eric E. Sumner Award “for pioneering contributions to the field of network coding.”