To identify the correlation between immune infiltrates and prognosis of cancer patients, we demonstrated that ERBB2 gain-of-function of primary tumor boosts macrophages, mast cells, NK cells, Th2 cells, and follicular helper T-cell cluster infiltration, apparently recruits follicular B helper T-cell-mediated adaptive immunity, and gradually drives away T regulatory cells that suppress or downregulate induction and proliferation of effector T cells. Here, ERBB2 is linked to cancer.