Xiangqi Liu, Xue‐Feng Zhang, J. C. Jiao, Renjie Zhang, K. W. Chen, Ying Wang, Yunguan Ye, Zhenhai Yu, Chengyu Jiang, Xia Wang, Bei Jiang, Yaobo Huang, Gang Li, Baiqing Lv, Gang Li, Yanfeng Guo
Correlated kagome metals host unique electronic states that enable exotic quantum phenomena. In the recently emerged CsCr_{6}Sb_{6}, these manifest through Kondo behavior from localized Cr-3d electrons and unprecedented band flattening near the Fermi level. Yet the intricate interplay among Kondo screening, magnetic frustration, and electronic correlations remains poorly understood-a fundamental gap we address through multifaceted experimental and theoretical approaches. Our angle-resolved photoemission spectroscopy measurements reveal electronic correlation-renormalized flat bands, and our muon spin relaxation study detects short-range magnetic order at T_{N}∼80 K. Complementing these findings, density-functional theory and dynamical mean-field theory calculations identify a coherent-incoherent crossover at T_{N}, with a remarkable restoration of coherence accompanying local moment suppression-an anomalous hallmark of Kondo behavior. Intriguingly, despite strong interlayer antiferromagnetic coupling, the system evades long-range magnetic order due to competing magnetic configurations separated by sub-meV energy differences. These insights establish CsCr_{6}Sb_{6} as a prototypical platform for investigating dynamical Kondo screening in correlated flat-band systems, opening new avenues to study flat-band physics and frustrated magnetism in correlated kagome lattices.