For standard run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Kernel:firmware/standard/Kernel:firmware.repo
zypper refresh
zypper install kernel-firmware-iwlwifi
For 16.0 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Kernel:firmware/16.0/Kernel:firmware.repo
zypper refresh
zypper install kernel-firmware-iwlwifi
For 15.6 run the following as root:
zypper addrepo https://download.opensuse.org/repositories/Kernel:firmware/15.6/Kernel:firmware.repo
zypper refresh
zypper install kernel-firmware-iwlwifi