Cinque Terre Hiking and Train Card

The Treno card includes everything in the Trekking card plus the trains, so you don't need both. However, if you're only taking the train once, it might be cheaper to buy the Trekking card and individual tickets.

This very recent thread might be helpful:

https://community.ricksteves.com/travel-forum/italy/cinque-terre-trenord-ms-card-question

As above, if only planning on hiking the "Blue" and taking the train only once or twice, a Trekking card +individual train tickets is the more cost-effective option. Be sure and validate those tickets before you board.

Important notes about the "Blue": you cannot hike it all the way from Vernazza to Riomaggiore as the section between Corniglia and Manarola is closed. It has been closed to landslide damage for many years. there is an alternative way around it but longer and more strenuous so if not up to it then you might want to take the train between Corniglia and Manarola, and again between Manarola and Riomaggiore.

The Manarola> Riomaggiore section is known as the Via Dell Amore and requires a timed-entry reservation + additional fee to access (from its entry point in Riomaggiore.) Use the link to the park (https://www.parconazionale5terre.it/Eindex.php) and cinqueterre.eu.com provided in the thread I linked above) for more info.