In vitro activation of mouse CD8+ T cells is frequently used in cancer, autoimmunity, and infection studies. However, the choice of activation protocol can significantly shape T cell differentiation, metabolic remodeling, and functional outcomes. These factors can influence both experimental interpretation and translational applications. Join Braden Kersey and Erin Tanaka from the Klein Geltink lab as they present a comparison of four widely used CD8+ T cell activation methods, and reveal how different stimulation approaches impact effector differentiation, mitochondrial phenotypes, and cytokine production.