“Digital in-line holographic microscopy (DIHM), a non-invasive, real-time, label-free technique, captures 3D positional, orientational, and morphological information from living biological cells. This review outlines the fundamental principles and comprehensive digital image processing procedures employed in DIHM-based cell tracking methods. Leveraging artificial intelligence has significantly enhanced both the speed and accuracy of digital image processing for cell tracking and identification, which provides solutions to solve problems in label-free identification and digital tracking of various motile biological cells.”