Some people do that successfully, but from a network management standpoint it’s much better to move your hub at least 2 m away from the Wi-Fi router. Just use a long cable.
You can also check the channels for both Wi-Fi and Zigbee to limit interference.
Wi-Fi and Zigbee transmit in the same frequency, but Wi-Fi is much much stronger, so it can drown out zigbee. That might then require zigbee messages to be sent three or four times before they get through, which can introduce lag or cause a device to be marked off-line when it isn’t.
FAQ: Networking and Reducing Channel interference between WiFi and Zigbee
If you have your smartthings hub right next to your Wi-Fi router and everything is working fine, you don’t have to worry about it.
But if your zigbee devices are getting a high rate of error transmissions or are off-line, then it may be time to consider more separation or changing channels. 