“…Recently, there has been an increase in the number of publications related to the definition of synergism, such as the “lack-of-fit” model ( Lederer et al., 2019 ) or the rediscovered Hand model ( Hand, 2000 ; Sinzger et al., 2019 ). Novel ways to evaluate synergism in drug combination studies also appeared such as the ZIP model ( Yadav et al., 2015 ), Combenefit (SANE) ( Di Veroli et al., 2016 ), Bivariate Response to Additive Interacting Doses (BRAID) ( Twarog et al., 2016 ), Schindler's Hill partial differential equation ( Schindler, 2017 ), the SynergyFinder software ( Zheng et al., 2022 ), the Multi-dimensional Synergy of Combinations (MuSyC) ( Meyer et al., 2019 ), the effective dose model ( Zimmer et al., 2016 ) and the copula model ( Lambert and Dawson, 2019 ), for example. Next, we will describe some of the most common methods for directly quantifying and evaluating drug synergism ( Ma and Motsinger-Reif, 2019 ).…”