Gianfranco De Zotti obtained Bachelor degree (1970) and Advanced studies degree (PhD alike; 1975) in Physics from the University of Padua, Italy. Then, he worked as a researcher at the National Research Council, became a senior astronomer (equivalent to full professor) in 1986, and retired on 2012. He was the Director of the Astronomical Observatory of Padova from 1991 to 1999. Sine 1986 and for nearly 30 years, he was a guest professor at SISSA in Trieste and had taught courses in Astrophysics and Cosmology there. He was also a member of many astronomy working groups and committees, such as a Co-I of the Planck mission and a coordinator of its "Astrophysical foregrounds" project. His research has covered a wide range of issues in extragalactic astrophysics and cosmology. Hitherto, he has more than 700 scientific publications with over 96,000 total citations and an H-index of 128.The correlation between the total infrared (8-1000 μm) and radio luminosity of star-forming galaxies, covering about five orders of magnitude, is one of the tightest correlations in astrophysics. Although it has been discovered about 40 years ago, it is still far from being understood. In recent years, evidence of a redshift evolution of the correlation has been raising further problems about the underlying physics. In this talk, I will present a new interpretation of the origin of such correlation, linking it to the different galaxy populations which dominate the cosmic star-formation rate at different epochs.