Metabolic dysfunctions associated with obesity and aging profoundly alter immune responses, however, there is little understanding of mechanisms that align functions of immune cells with their metabolic and physiological environment. We found a new mechanism of the metabolic reprogramming of dendritic cells by excessive dietary fatty acids that initiates a specific inflammatory program which contributes to exacerbated psoriatic skin inflammation in obesity (Mogilenko et al. Cell. 2019). Comprehensive profiling of an aging immune system in mice and humans revealed that an aged environment induces the development of “exhausted-like” GZMK⁺CD8⁺ T cells that can enhance “inflammaging” (Mogilenko et al. Immunity. 2020).