Have a solid ground plane and ground vias under the module for stable system and thermal dissipation.
Do not run signal traces underneath the module on a layer where the module is mounted.
RF traces must have 50-Ω impedance.
RF trace bends must be made with gradual curves, and 90 degree bends must be avoided.
RF traces must not have sharp corners.
There must be no traces or ground under the antenna section.
RF traces must have via stitching on the ground plane beside the RF trace on both sides.
RF traces must be as short as possible. The antenna, RF traces, and the module must be on the edge of the PCB product in consideration of the product enclosure material and proximity.