I will discuss the 4d Symmetry Topological Field Theory (Symmetry TFT) encoding generalized global symmetries and 't Hooft anomalies of 3d quantum fields theories with an M-theory realization. We will see how the Symmetry TFT is specified by the geometric data of the M-theory construction. We apply this in concrete examples of the AdS_4/CFT_3 correspondence with N=6 and N=2 supersymmetry, respectively. I will show how the Symmetry TFT determines the global form of the gauge group, and derive new 't Hooft anomalies for higher-form symmetries. Finally, we demonstrate how characterizing refined properties, such as the spectrum of line operators, provides new checks on the holographic dictionary in the context of (gauge) anomaly-cancellation in the N=2 theories.