echo "zabbix ALL=(ALL) NOPASSWD:/usr/sbin/smartctl" >/etc/sudoers.d/zabbix
systemctl restart zabbix-agent2.service

see https://www.zabbix.com/integrations/smart

Monitoring → Hosts - (Configuration: Host) → Add Template SMART by Zabbix agent 2 → Update

Dashboards - > Edit dashboard → Add widget → SMART XXXX : Temperature

Trend example