Drupal 8 Node Operations

<?php
 
$entity->hasField('abc');
?>

<?php
use Drupal\node\Entity\Node
$title = Node::load($nid)->get('title')->value;
$node = \Drupal::entityManager()->getStorage('node')->load($nid); //Another way to load
?>

<?php
$terms = $node->get('abc')->getValue(); 
$terms = $node->abc->getValue(); 
?>

<?php
 $nid = \Drupal::routeMatch()->getRawParameter($node_id); 
?>