Why is Listis not List although ClassA implements InterfaceA in Java

Question

I have an interface CPUStore that has the following function

List<ICPU> getAllCPUs();

CPURepository implements CPUStore, and CPUEntity implements ICPU When I try to do this, I'm getting an error since List<CPUEntity> isn't the same as List<ICPU>

  @Override
    public List<CPUEntity> getAllCPUs() {
        CriteriaBuilder builder = session.getCriteriaBuilder();
        CriteriaQuery<CPUEntity> criteria = builder.createQuery(CPUEntity.class);
        criteria.from(CPUEntity.class);
        List<CPUEntity> data = session.createQuery(criteria).getResultList();
        return data;
    }

I should have the code compiling but it's not