In the final moments before the crucifixion, Jesus gave the disciples another analogy on Jesus. Jesus told the disciples that "[He] is the true vine" and "Father is the vinedresser" (15:1). According to Merriam-Webster, a "vinedresser" is "a person who cultivates or prunes vineyards", so with the analogy, Jesus talks about how the Father is the manager of the vine thingy.
In particular, Jesus proclaimed that the Father "takes away" branches in Jesus (AKA the vine) and "prunes" branches with fruit (15:2). The saying can be a bit tricky to interpret; here are some possible interpretations.
1. Fruitless branches are "lifted up". The meaning of "lifted up" (Strong 142) is not only supported by the Interlinear but also by the cultural context of how vinedressing works. Thomas Constable note that the branches that get lifted up "get special attention from the vinedresser" in order to yield fruit (Study Light). John Niemelä went into more detail in this article.
2. Fruitless branches are "removed" since they aren't really believers. There are multiple instances of people who have experience in church-like areas yet never accept Jesus in the first place (case in point, Judas Iscariot). It's worth noting that belief is technically a fruit because we receive peace from God, and Jesus draws people to himself (as noted in John 12:32).
Jesus was speaking to the disciples (aside from Judas who ran out), who were "already clean" based on Jesus's words (15:3). Even though they are already clean (AKA "saved"), Jesus still calls them to "abide in [Him]" (15:4). According to Merriam-Webster, one of the meanings of "abide" is "to continue in a place", so based on the context, abiding in Jesus means continuing to count on Jesus. In fact, going back to the vine analogy, abiding is how we can bear more fruit. In fact, if we don't abide in Jesus, we can't bear more fruit.