Today, for patients with programmed cell death ligand 1 (PD‐L1) expression ≥50% of tumor cells (approximately one‐third of patients), immunotherapy or immunotherapy in combination with chemotherapy is the first‐line treatment option.6 For these patients starting with mono immunotherapy, recent studies already suggest the significance of both CEA and LDH for the assessment of treatment response,21, 22, 23, 24 which is in line with the findings presented here. The gene discussed is CEACAM5; the disease is neoplasm.