In HER2-positive GC, the phase III KEYNOTE-811 trial demonstrated that patients in the CPS≥1 subgroup had significantly higher benefits of overall survival after treatment with pembrolizumab, trastuzumab and chemotherapy, while those in the CPS<1 subgroup hardly gained clinical benefits (24), highlighting the differences in tumour immune microenvironment features between PD-L1 positive and negative patients. Here, ERBB2 is linked to gastric cancer.