  We explicitly determine the defining relations of all quantum symmetric pair
coideal subalgebras of quantized enveloping algebras of Kac-Moody type. Our
methods are based on star products on noncommutative $\mathbb{N}$-graded
algebras. The resulting defining relations are expressed in terms of continuous
q-Hermite polynomials and a new family of deformed Chebyshev polynomials.
