In GI cancer, the PD‐L1 IHC 22C3 pharmDx assay was approved as a companion diagnostic for pembrolizumab in advanced EC (based on the KEYNOTE‐180 and KEYNOTE‐181 trials) and in advanced GC and GEJ cancer (based on the KEYNOTE‐059 trial). The gene discussed is CD274; the disease is gastric cancer.