In this context, the authors suggested that baseline high levels of EV PD-L1 may indicate a T cell exhaustion, while increased levels of EV PD-L1 levels following immunotherapy could be related to reinvigoration of T cells and an improved anti-tumor immune response which is more pronounced in responders as they have a ‘less exhausted’ pre-existing tumor immunity when compared to non-responders whose T cells can no longer be recovered with immunotherapy [157, 289]. Here, CD274 is linked to neoplasm.