CD28 and coinfection: The positive correlation between inflammatory cytokines (e.g., IFN‐γ) and the percentage of CD8 + CD28+ T cells exhibiting low MMP strongly suggests that, within the extreme inflammatory context of HIV‐TB co‐infection, high levels of pro‐inflammatory signals are not promoting the functional activation of CD8 + CD28+ T cells but are instead closely associated with the dysfunction and reduced survival capacity of these crucial effector cells.