The disclosure herein relates to systems, methods, and devices for decreasing latency and/or preventing data leakage that may arise from advertisement insertion. In some embodiments, the systems, methods, and devices described herein provide for asynchronous advertisement selection and/or insertion separate from user-requested content retrieval and/or delivery, wherein the advertisement selection can be performed in parallel with and/or at a separate location from the user-requested content retrieval and/or delivery, thereby decreasing latency in rendering user-requested content. Further, in certain embodiments, the systems, methods, and devices described herein can prevent data leakage by preventing and/or circumventing the need to use cookie syncing among different DSPs, SSPs, or the like. Moreover, in some embodiments, the systems, methods, and devices described herein are configured to deliver advertisements as a native content, thereby further decreasing latency and/or preventing data leakage.