Redis is not only for cache, but extra features such as persistence, publish and subscribe.

Difference between Redis PubSub vs RabbitMQ

Redis Pub SubRabbitMQ
Used for simple publish and subscribe messageStable, reliable message and enterprise pub sub
Not store messages during failovers in listernerStore the messages for failover in listeners
No Support queues or point-to-point communicationSupport for point-to-point queue and pub sub