SAMPL (Statistical Assessment of the Modeling of Proteins and Ligands) is a set of community-wide blind challenges aimed to advance computational techniques as standard predictive tools in rational drug design. A broad range of biologically relevant systems with different sizes and levels of complexities including proteins, host–guest complexes, and drug-like small molecules have been selected to test the latest modeling methods and force fields in SAMPL. New experimental data, such as binding affinity and hydration free energy, are withheld from participants until the prediction submission deadline, so that the true predictive power of methods can be revealed. The most recent SAMPL5 challenge contains two prediction categories: the binding affinity of host–guest systems, and the distribut