The ADO Bus terminal serves first class buses  to many

 locations in Mexico including Cancun  Airport, 

Chichen Itza, Merida, and Tulum.

Cancun Airport Transfer

There are several options for airport transfer from Cancun's airport to the hotel zone or to Playa del Carmen.  

• Collective Taxi

There are collective taxis (colectivos explained) and there is the public bus.  These are the bargain options.
The collective taxis are a good option for transfer to the hotel zone, about 12 miles from the airport.  (Private taxis are not allowed to pick up passengers at the airport, they can only drop off passengers.)
I prefer the colectivos, they are reasonable and comfortable.  They drop you at your hotel.

•  Public Bus

The public bus is an option but it will make many stops and could result in a long trip and could be difficult if you have excess luggage.  The local bus is great for a short trip but you start feeling like you are in the middle of the morning commute after a few miles. 
I like the public bus system for trips between beaches in the hotel zone, short trips to the restaurants etc.  The trip from the ADO station to the hotel zone is about the max for me on the public bus.

• Shared Shuttle

A good option for airport transfer is the many shuttle services both private and shared that run to the hotel zone, to the Cozumel ferry dock, and to Playa del Carmen from the Cancun Airport.   

• Private Shuttle

You can search online ahead of your trip and book a shared or private shuttle for airport transfer to the Cancun hotel zone, Cozumel boat dock, or Playa del Carmen. This will save you from the gauntlet of hawkers who will greet you on arrival.  

• ADO Airport Bus Terminal

Another good option is the ADO first class bus service that is available at the airport.    ADO buses make a regular run from the airport to the ADO first class bus station in Cancun.  From there, ADO serves all parts of Southern Mexico and includes Mexico City through the various cities along the way such as Villahermosa, Oaxaca, and Veracruz.  

ADO bus service is available from terminal 2, domestic flights,  and terminal 3, international flights.  ADO Buses reach Playa del Carmen in about one hour.  I like the ADO option when I am traveling through Cancun and headed for Tulum or Chichen Itza.

• Vendors

You are apt to encounter many sales people, time share sales people etc on arrival who offer bus service transfer and the like, beware.

Several Public beaches in the hotel 

zone can be reached by public bus.

ADO or a shared shuttle will be the best options and you won't suffer through a timeshare pitch.   

ADO will take you to the Cancun ADO station and from there you can get a local for the hotel zone if that is where your hotel is located.  (this is not a bad option unless you have a lot of luggage)  
I have taken ADO first class buses from the Cancun ADO Bus Station to Tulum, Chichen Itza, Chetumal, Valladolid,  and Merida.
You can reach much of Mexico by first class bus from the Cancun ADO Station.
At the Tulum ruin site I could have bought onward transportation via ADO at their small Tulum station but instead went across the street and caught the colectivo that runs between Playa Del Carmen, Tulum, and Tulum City.  I wanted to see Tulum City before I headed south west to Chetumal on my way to Tikal.  

Cancun Local Bus