Vanishing of relative cohomology with the off-diagonal

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Let $X$ be a connected space, and $\Delta_n: X \rightarrow X^n$ be the diagonal embedding. Are there "mild" conditions on $X$ which guarantees the vanishing of the relative (singular) cohomology $H^k(X^n, X^n - \Delta_n(X) ; \mathbb{Z})$ when $n$ is relatively large compared to $k$?