Similarly, in the KATE2 trial, where 202 advanced HER2+ BC patients received the combination of either TDM1+placebo or TDM1+atezolizumab, a borderline significant association was found between higher TILs (≥5%) and increased benefit from the addition of immunotherapy to anti-HER2 treatment, thus strengthening the potential predictive role of TILs in terms of immune checkpoint blockade efficacy [90,91]. Here, ERBB2 is linked to breast cancer.