PDCD1 and neoplasm: Thus, when CD8+ T cells are lacking inside tumour lesions, patients do not respond to PD‐1/PD‐L1 blockade therapy.51 If CD8+ T cells inhibited by PD‐1/PD‐L1 are present in inadequate numbers within the tumour microenvironment, then PD‐1/PD‐L1 blockade therapy would be unlikely to work.49