Yongnuo only makes two types of flashes with built-in radio triggers: manual-only flashes (YN-560III & YN-560IV), and the Canon-RT compatible flash, the YN-600EX-RT. The YN-565EX/568EX/500EX (and MkIIs) models do not have a radio receiver built in. (The YN-685 apparently has a YN-622/RF-603/RF-605 receiver in it).
The built-in slave modes on the YN-565EX are optical (light-based), not radio. It can be used in Nikon's CLS (or Canon's wireless eTTL) system, and can be used as a "dumb" optical slave to fire from a flash burst from any flash (similar to SU-4 mode on a Nikon speedlight). Optical-based triggering, though, has range of line-of-sight requirements that become more stringent and restrictive if you're shooting outdoors and in bright sunlight.
The YN-560-TX transmitter is a "manual" trigger: it can only tell a flash when to fire, and it works with the YN-560III and YN-560IV speedlights, and the RF-602, RF-603, RF-603II, and RF-605 radio trigger units. So, to trip a YN-565EX from a YN-560-TX, you need to add on a radio receiver unit. However, the only control you have over the remote flash is firing it. You cannot use iTTL, FP/HSS, or remotely control the power level/zoom of the flash. The YN-560-TX can only control the power/zoom/group of the YN-560III and YN-560IV.
The YN-565EX/YN-568EX, however, can be used with i-TTL, FP, remote power, etc. etc. if you use a YN-622N transceiver as a receiver on the flash, and another YN-622N or the YN-622N-TX as the commander unit on the camera's hotshoe.
See also: What are the Yongnuo flash naming conventions?