The field of computer vision is witnessing significant advancements in 3D object detection and crowd analysis. Recent developments have focused on improving the accuracy and efficiency of 3D object detection models, particularly in scenarios involving point clouds and crowded scenes. Researchers have proposed innovative solutions, such as slice-based representations and dual-stream graph convolutional networks, to address the challenges posed by complex environments. Furthermore, there is a growing interest in developing models that can effectively estimate crowd density and detect objects in crowded scenes, with applications in areas like autonomous driving and surveillance. Notable papers in this area include PointSlice, which achieves high detection accuracy and inference speed, and CrowdQuery, which introduces a density-guided query module for enhanced 2D and 3D detection in crowded scenes. Overall, these advancements have the potential to significantly impact various applications and pave the way for future research in this field.