I understand that you want to read distance data from an Arduino sensor and use it in Simulink.
You can use serial port 0 to communicate with other devices that have serial ports, or to communicate with a computer over the USB port. Each serial port supports one Serial Transmit and one Serial Receive block, one block per pin. You can run your model in the External mode for all the Arduino boards.
Also, you can refer to the below documentation to know about the detailed process of transmitting and receiving serial data –
