Regrettably, there are no closed expressions for integration over the unitary group of rational functions, only for polynomials. There are asymptotic results for large $d$, see for example <A HREF="https://arxiv.org/abs/cond-mat/9604059">J. Math. Phys. 37, 4904 (1996)</A>. The leading order term is
$$\int_{\mathbb{U}(d)}\dfrac{1}{\sum_{k,l}u_{ik}\overline{u_{il}}c_{kl}}dU\rightarrow \frac{d}{\sum_{i}c_{ii}}.$$