This work aims to elucidate the molecular mechanisms by which lactate promotes tumor DNA damage repair (DDR) and subsequent immune evasion.<h4>Methods</h4>Hepatocellular carcinoma (HCC), lung adenocarcinoma (LUAD), and ovarian cancer (OC) cells with cisplatin-induced DNA damage were treated with lactate at a concentration gradient, Endothelial cell-specific molecule 1 (ESM1) shRNA, ESM1 overexpression plasmid, or the Protein Kinase B (AKT) Serine/Threonine Kinase 1 (Akt1) inhibitor LY294002. Here, AKT1 is linked to lung adenocarcinoma.