The official high-resolution texture pack for Sleeping Dogs is available as free downloadable content (DLC) on Steam for owners of the original game.
For enthusiasts who want more than the official pack, the Sleeping Dogs modding community has created “Super HD” packs and upscaled textures using AI tools (e.g., ESRGAN). The most notable is presets combined with texture mods from Nexus Mods. Examples include: Sleeping Dogs Hd Texture Pack Download Skidrow