<p>The Atacama Large Millimeter/submillimeter Array and the James Webb Space Telescope are transforming our understanding of galaxy formation and evolution in the early Universe. By combining their capabilities, these observatories provide unprecedented insights into the gas, dust and stars of high-redshift galaxies at spatially resolved scales, unveiling the complexities of their interstellar medium, kinematics, morphology, active galactic nuclei and star-formation activity. This review summarizes recent breakthroughs in the study of galaxies during the first billion years of cosmic history, highlighting key discoveries, open questions and current limitations. We discuss how observations, theoretical models and simulations are shaping our understanding of early galaxy evolution and identify promising directions for future research. While substantial progress can be achieved through optimized use of existing facilities and collaborative efforts, further advances will require enhanced angular resolution and sensitivity, motivating upgrades to current instruments and the development of next-generation observatories.</p>