The HP Pavilion 15-cc507nf notebook comes up with a wifi adapter Realtek rtl8723de not detected after a fresh install of Debian Stretch.
Realtek firmwares are provided by the firmware-realtek package.
After enabling the Stretch-backports, a newer kernel version is available 184.108.40.206 and a newer version of the Firmware-realtek in Stretch backports
This one contains the wifi firmware for rtl8723de : Realtek RTL8723DE firmware (rtlwifi/rtl8723defw.bin)
Just install them and make sure to boot on this latest kernel version. The integrated wifi card is now available for configuration and for use.