ARID1A and gastric cancer: Previous studies have highlighted the significance of mutations in specific genes such as ARID1A,[14]PIK3CA,[15]KMT2D, and SYNE1 in influencing the response to immunotherapy with ICBs.[16] Our previous data also indicated that mutations in ARID1A and PIK3CA were associated with increased immune infiltration and higher TMEscore in gastric cancer,[9] which could potentially enhance the efficacy of anti‐PD‐1/PD‐L1 immunotherapy.