The continued buildout of 5G cellular networks on a hodgepodge of spectrum has made the probability of interference inevitable. There are three main categories of interference that operators experience: 1) passive intermodulation and other localized interferers on the tower/site, 2) external interference from environmental such as electronics or wireless devices, and 3) interference with other carriers using the same licensed spectrum. What are the causes of this and how can operators design and build 5G networks to prevent, or at least mitigate, this interference?