PDCD1 and neoplasm: Overall, the anti-tumor effect observed in the mice actively immunized with the mPD1-derived mimotope may not solely be linked to the capacity of the induced antibodies in inhibiting the interaction between PD1 and PD–L1, as the amount of antibodies induced by active immunization were clearly lower than the passively transferred antibody levels, indicating that active immunization induces broader immunological and cellular effects, in which pathways need subsequent in-depth analysis.