“…We have revisited the many approaches available to explore the FEL of proteins, optimizing hardware, software and algorithms pursuing the dream of the seconds-long sampling. From a completely different standpoint, simulations in crowded cell-like soups of multiple copies of the same protein, although still in the ns-scale, are already a reality that holds promise to reveal dynamical complexity in local microenvironments, providing yet another approach to the sampling problem (Yu et al, 2016; Feig et al, 2018). We have also briefly mentioned machine learning algorithms, paradigmatic of a series of novel fast-developing non-physically based strategies which are gaining ground to study transitions, either alone or in combination with MD or CG-methods: from co-evolution analysis (Morcos et al, 2013; Sutto et al, 2015; Sfriso et al, 2016) to cross-correlation, network and community approaches (Potestio et al, 2009; Morra et al, 2012; Rivalta et al, 2012; Papaleo, 2015; Negre et al, 2018), neural networks and deep learning (Ung et al, 2018; Degiacomi, 2019), or integrative sequence and structural analysis (Flock et al, 2015).…”