In fact, the tumor mutational burden and the presence of tumor infiltrating lymphocytes (TILs), which clearly correlate with clinical outcomes,3–5 are higher among triple-negative (TNBC) and human epidermal growth factor receptor 2 positive (HER2+) breast carcinomas than in ER+ tumors.6 Based on the observed responsiveness of highly mutated tumors with high infiltration of immune cells to immunotherapeuticals, HER2+ remains an optimal setting to explore the efficacy of cancer immunotherapy (CIT). Here, ERBB2 is linked to cancer.