Cellular senescence is implicated in numerous biological processes, and can play pleiotropic, sometimes opposing, roles in cancer. Several triggers, cell types, contexts, and senescence-associated phenotypes introduce a multitude of possibilities when studying this process and its biological consequences. Recent studies continue to characterize cellular senescence at different levels, using a combination of functional screens, in silico analysis, omics characterizations and more targeted studies. However, a comprehensive analysis of its context-dependent effects and multiple phenotypes is required. Application of state-of-the-art and emerging technologies will increase our understanding of this complex process and better guide future strategies to harness senescence to our advantage, or to target it when detrimental.