Since its discovery in 2019, lactylation has emerged as a critical posttranslational modification with significant implications for cancer biology. Lactylation involves lactyltransferase-mediated addition of lactate to lysine residues on both histone and nonhistone proteins. In this study, we summarize key advances in research on lactylation and cancer. Lactylation functions in tumor progression and represents a therapeutic target and biomarker. The field currently faces many challenges, such as identifying specific "readers" of lactylation and developing precise tools for studying its biological impact. This perspective aims to provide insights into the role of lactylation in cancer and to stimulate further exploration.