The goal was to compare the 5‐year DFS and 5‐year OS in patients with early‐stage human epidermal growth factor receptor 2 breast cancer (HER2+ BC) and triple‐negative breast cancer (TNBC) in relation to the amount of stromal tumor‐infiltrating lymphocytes (TILs) after locoregional management by either mastectomy without radiation or lumpectomy and whole‐breast radiotherapy (RT). Here, ERBB2 is linked to neoplasm.