$x^{5} \cdot x^{3}$
So, the final answer is \(\boxed{x^{8}}\)
Step 1 :Understand the problem: We are asked to simplify the expression $x^{5} \cdot x^{3}$.
Step 2 :Recall the rule of exponents: $a^{m} \cdot a^{n} = a^{m+n}$.
Step 3 :Apply the rule to the given expression: $x^{5} \cdot x^{3} = x^{5+3}$.
Step 4 :Perform the addition in the exponent: $x^{5+3} = x^{8}$.
Step 5 :Check the result: $x^{8}$ is indeed the simplest form of the expression $x^{5} \cdot x^{3}$.
Step 6 :So, the final answer is \(\boxed{x^{8}}\)