The spatiotemporal behavior of CD8+ T cell cytokines is likely to depend on A) the mode of cytokine secretion by the producing cell, and B) environmental factors influencing receptor-mediated clearance, cytokine half-life, cytokine binding to extracellular components, and feedback/ feedforward loops. Variation between these factors is expected between tumors, due to e.g. their genetic make-up, immune infiltrate, molecular ECM structure, level of hypoxia, and nutrient availability.