You can reach the Campus by means of
By train: with stop in "Cantoblanco Universidad"
Line C-4a Parla-Atocha-San Sebastián de los Reyes
Line C-4b Parla-Atocha-Colmenar Viejo
Regional buses with stop in "Univ. Autónoma - Cantoblanco":
Bus 714: Plaza Castilla - Cantoblanco - Comillas
Bus 827: Alcobendas - Cantoblanco
Bus 827A: San Sebastián de los Reyes - Alcobendas - Cantoblanco
Specifically from the Airport to Campus UAM Cantoblanco:
By bus: (From Terminal 4) Bus 827, 827A, 828 to Alcobendas - Universidad Autónoma, stop in "Universidad Autónoma - Calle Marie Curie". One-way tickets are 2EUR.
By train: (From Terminal 4) Line C-1 direction Atocha-Principe Pio, stop in "Chamartin". From Chamartin change to line C-4a (direction Alcobendas- San Sebastián de los Reyes) or C-4b (direction Colmenar Viejo), stop in "Cantoblanco Universidad". One-way tickets are 2.5EUR.
By metro: Metro Line 8, stop in "Nuevos Ministerios". From Nuevos Ministerios, change to take the train. Take the train line C-4a (direction Alcobendas- San Sebastián de los Reyes) or C-4b (direction Colmenar Viejo), stop in "Cantoblanco Universidad". Metro tickets from airport are about 5 EUR (airport adds extra cost). Metro tickets are different from train tickets, to be bought separately.
By taxi: Taxi is normally cheaper than Cabify or Uber. Range: 20-30 EUR, depending on the size of the car. The app for taxi is "mytaxi".