It can mean just that.
When a life sentence is passed, the minimum sentence the judge gives (for example, 10 years) is how long the person must serve before they can be considered for release on license. To even be considered for this release they have to be making a real effort to engage with the programmes prison offers for things like cognitive behavioural therapy, anger management, etc, designed to make them understand why they killed, why it's a bad thing and how to control their violent impulses. They also have to show genuine remorse for their actions.
Some especially heinous criminals are given a whole life tariff; this means they will never even be considered for release under license.
Even if they are eventually released on license, they are still monitored by the probation service and can be recalled to prison if they behave in such a way that they are thought to be at risk of committing another offence of any kind. This oversight can last for many years.
If they don't engage with these programmes, or they don't do any good, they will not be released. A well known prisoner who has fallen foul of this condition is Harry Roberts, who shot and killed two policemen during a robbery in 1966. He's still in prison.