Fusion energy has been the driving force in the High Energy Density (HED) community for more than fifty years but especially since the start of the National Ignition Campaign in 2009 at the National Ignition facility (LLNL, USA). The National Ignition Campaign, though a marvel in terms of laser technology and data quality in this challenging regime, has failed to achieve ignition. This failure has shed light on gaps in our understanding of fundamental plasma properties such as thermal transport or emissivity. Following these initial difficulties, the evolution of the design (higher adiabat, new ablator, new hohlraum conditions) has led to significant improvement in implosion performance over the years and finally to ignition (Q=1.5) in December of 2022. I will go over these evolutions and why they led to the recent successes obtained on the NIF.