Is CDHP (Consumer Driven Health Plan) the same as HDHP (High Deductible Health Plan) for tax purposes?

A CDHP (Consumer Directed Health Plan) is an industry (i.e., not IRS) term for the combination of an HDHP and a tax-advantaged plan for the deductible like an HSA (there could be other plans). That is, CDHP is used as a short-cut term for the pairing.

So, having a CDHP is not inconsistent with having an HDHP - in fact, a CDHP normally assumes that you have an HDHP as your regular health insurance.

If you have a code "W" in box 12 on your W-2, then your employer believes that your health plan is a qualified HDHP. Indeed, your employer should know; they acquired the plan.

If you have this code, either you have an HDHP or your employer made a mistake on your W-2 and you need it corrected...but you probably have an HSA and an HDHP...called a CDHP by your HR department and your benefits company.