CEACAM5 and neoplasm: In a more recent study, the same HIFα sensing domain was fused to a CAR‐T specific for the carcinoembryonic antigen (CEA), obtaining also here a CAR‐T activation highly restricted to the hypoxic tumor environment (Figure 2DI).[49] This approach can minimize the off‐target cytotoxicity as the CAR stops functioning in a normoxic environment.