Amazon MSK is best labeled as an alternative to Kinesis, they both allow you to stream data taking input from producers and having data pulled from them by consumers. MSK allows you have run a fully managed Apache Kafka cluster on AWS, MSK will create and manage nodes, is highly available with 3 AZ, automatic recovery from failure, and stores data on EBS volumes.
You can also use a serverless alternative of MSK, that will provision capacity automatically and does not need to be managed. As opposed to Kinesis, Kafka does not have a 1 MB message limit, has TLS encryption, KMS at-rest encryption, and has a similar function to shards in Kinesis called Kafka topics with partitions.