Using LTE in unlicensed bands will allow operators to access additional spectrum to meet the increasing demand for mobile services. In this article, we provide an overview of the different approaches currently being considered for LTE operation in unlicensed bands and their interaction with WiFi networks. In summary, LTE-Unlicensed with carrier sense adaptive transmission is likely to be available in the short term, but cannot be used in all regions due to regulatory restrictions. License assisted access is intended for use more widely, so it will include listen-before-talk and other features required to conform with, for example, European and Japanese regulations. However, this will require changes to the LTE standards, so license assisted access is likely to take longer to deploy. In addition to describing the trade-offs between these approaches, we also discuss the issue of fair coexistence with existing unlicensed band users, especially WiFi devices.