Higher tumor PD-L1 expression was reported in most MSI-H GC using CPS compared with MSI-stable GC.50 In the CheckMate 649 study, 4% (18/473) and 3% (16/482) of patients with a PD-L1 CPS of ≥5 had MSI-H tumors in the nivolumab plus chemotherapy and chemotherapy alone groups, respectively,51 and some MSI-H patients may not express PD-L1 at high levels or may have a CPS of 1–5.50,52 However, we must note that differences exist in antibody IHC assays (22C3 and 28-8Ab), definitions and cutoffs of CPS, and methods for detecting MSI (IHC vs PCR). The gene discussed is CD274; the disease is neoplasm.