I will discuss the role that dark matter may play in relieving tensions in cosmology and how this effect can (and may already) be measured from the Integrated Sachs-Wolfe effect from cosmic voids. I consider a phenomenological model of dark matter with an equation-of-state that is negative and changing at late times, a model degenerate with interacting dark matter — dark energy models. I show this couples the H0 and σ8 tensions, providing an explanation for both simultaneously, while also providing an explanation for the anomalously large integrated Sachs-Wolfe (ISW) effect from cosmic voids. Observations of high ISW from cosmic voids may therefore be evidence that dark matter plays a significant role in the H0 and σ8 tensions. I predict the ISW from cosmic voids to be a factor of ~ 2 greater in this model than what is expected from the standard model ΛCDM. I will also discuss the general prospects for new-physics in cosmology and emphasise the need for new-physics solutions to tensions to be tested and validated with other anomalies and unique predictions/consequences.