Various embodiments generally relate to a semiconductor device, and more particularly, to an operating method of a controller and a memory system. In accordance with an embodiment of the present disclosure, an operating method of a controller for controlling a nonvolatile memory device including a plurality of memory blocks may include: generating High Performance Booster (HPB) data based on Logical to Physical (L2P) map data and storing the HPB data into at least one empty page included in a first memory block; assigning a second memory block when a number of empty pages included in the first memory block becomes smaller than a threshold number; and migrating HPB data, which is selected according to a predetermined criterion among the HPB data stored in the first memory block, into the second memory block, wherein at least a part of the HPB data is cached into a memory of a host.