The Events Calendar: Get all the Upcoming Events assigned a specific Event Category.

functions.php

<?php

/**
 * The Events Calendar: Get all the Upcoming Events assigned a specific Event Category.
 *
 * A utility function to be used as part of a bigger customization.
 *
 * @link https://gist.github.com/cliffordp/62360de9f1cb2b7b55b9bed080c173a6 This snippet.
 * @link https://theeventscalendar.com/knowledgebase/using-tribe_get_events/
 *
 * @see tribe_get_events()
 *
 * @param int $event_category_term_id The Term ID of an Event Category.
 *
 * @return array
 */
function cliff_tec_get_all_upcoming_events_from_event_category( $event_category_term_id = 0 ) {
	$event_category_term_id = (int) $event_category_term_id;

	$upcoming_events_in_event_category = array();

	if (
		class_exists( 'Tribe__Events__Main' )
		&& 0 < $event_category_term_id
	) {
		$upcoming_events_in_event_category = tribe_get_events(
			array(
				'posts_per_page' => -1, // unlimited
				'tax_query'      => array(
					array(
						'taxonomy' => Tribe__Events__Main::instance()->get_event_taxonomy(),
						'terms'    => $event_category_term_id
					)
				),
			)
		);
	}

	return $upcoming_events_in_event_category;
}