ERBB2 and breast cancer: Large-scale studies have found that more tumor-infiltrating lymphocytes are linked to prolonged survival of patients with early TNBC[29] and metastatic HER2-positive breast cancer.[30] The disappointing response rate is not more than 22% with immune monotherapy,[31,32] but in recent trials, chemotherapy has been added to improve the response to immunotherapy in some populations of breast cancer patients.