Connecting Adafruit 2.8" TFT Touch Shield to a Photon

[ScruffR]

That link clearly states

We also include an SPI touchscreen controller so you only need one additional pin to add a high quality touchscreen controller.

and on the board you see a silk note TS CS #8 - that's the SPI chip select for the touch screen.
So you only need one extra pin to control the CS pin on the display to actually talk to the touch controler.

Here yo can find the wiring info for TFT, resistive TouchScreen & SD

Adafruit 2.8" TFT Touch Shield v2 - Capacitive or Resistive

Note that the first three pins are always the same (SPI CLK, MOSI, MISO), only the CS pins need to be seperate (and the TFT also wants a D/C pin).