Recent studies have elucidated critical metabolic mechanisms shaping immune cell behavior. Research highlights glucose metabolism's central role in steering CD4+ T cell differentiation, fundamental to adaptive immunity. In oncology, discoveries include connexin 43's modulation of DNA repair affecting BRAF/MEK inhibitor efficacy and metabolic reprogramming within melanoma tumors influencing immune evasion. These findings underscore metabolism as a nexus for immunotherapy optimization and novel therapeutic targeting across cancer and infectious diseases.