PDCD1 and neoplasm: In Model 3, we radically remove the recurrent xenograft from tumour‐bearing mice treated with the anti‐PD1 antibody alone of Model 1 and re‐transplanted 1×1 mm3 recurrent tumour derived from the anti‐PD1 antibody‐treated group into the contralateral subcutaneous of the same mouse (Figure 5C).