"ip route get 8.8.8.8" equivalent in Mac?
You can simply use the route(8) command
$ route get 8.8.8.8
   route to: dns.google
destination: default
       mask: default
    gateway: 192.168.0.1
  interface: en0
      flags: &lt;UP,GATEWAY,DONE,STATIC,PRCLONING&gt;
 recvpipe  sendpipe  ssthresh  rtt,msec    rttvar  hopcount      mtu     expire
       0         0         0         0         0         0      1500         0

The ip tool is not supported on MacOS because it's a very Linux-specific implementation (Netlink). The Mac version of route uses another interface (see man 4 route).