PDCD1 and neoplasm: Notably, profiling of exhausted T cells revealed expression of several other exhaustion-related immune-checkpoint receptors, such as T cell membrane protein 3 (TIM-3) or lymphocyte-activation gene 3 (LAG-3) [44] and the outcome of ICI therapies may depend on the exact composition of PD-1 positive immune cell subsets as well as their complex spatiotemporal dynamics in their interaction with tumor cells.