CD8A and neoplasm: This section focuses on indirect TME-driven suppression, delineating how tumor cells and stromal elements orchestrate CD8+ T cell suppression through metabolic competition (e.g., nutrient deprivation), intercellular communication (eg. exosomes, tunneling nanotubes, or trogocytosis), and microenvironmental perturbations (eg. cytokine networks, ionic imbalances, or ammonia accumulation) (Table 1).