Let $\mathrm{Map}(X,Y)$ denote the (unbased) cellular mapping space from $X$ to $Y$. If $X$ and $Y$ are finite CW complexes, is $\mathrm{Map}(X,Y)$ a CW complex? Can we know the cell structure of $\mathrm{Map}(X,Y)$? For example, what is the cell structure of $\mathrm{Map}(S^n,S^k)$ for $n \geq k$? Please recommend related papers and textbooks.