The article reviews the metabolic processes that drive T cell development, activation, and differentiation. It highlights the critical role of metabolic pathways in regulating lymphocyte signaling, function, and fate. Key metabolic pathways, such as aerobic glycolysis and oxidative phosphorylation (OXPHOS), are engaged during T cell activation, leading to biomass accumulation and enhanced effector function. The review also discusses the importance of specific metabolites and signaling molecules, such as adenosine and reactive oxygen species (ROS), in modulating T cell responses. Additionally, it explores the role of amino acids, lipids, and energy sensors like AMPK and mTOR in shaping T cell metabolism and function. The article concludes by discussing emerging topics in immunometabolism, including the connection between metabolism and gene regulation, and the potential implications of one-carbon metabolism in cancer research.The article reviews the metabolic processes that drive T cell development, activation, and differentiation. It highlights the critical role of metabolic pathways in regulating lymphocyte signaling, function, and fate. Key metabolic pathways, such as aerobic glycolysis and oxidative phosphorylation (OXPHOS), are engaged during T cell activation, leading to biomass accumulation and enhanced effector function. The review also discusses the importance of specific metabolites and signaling molecules, such as adenosine and reactive oxygen species (ROS), in modulating T cell responses. Additionally, it explores the role of amino acids, lipids, and energy sensors like AMPK and mTOR in shaping T cell metabolism and function. The article concludes by discussing emerging topics in immunometabolism, including the connection between metabolism and gene regulation, and the potential implications of one-carbon metabolism in cancer research.