Multiclassing is never mandatory to be effective in Dungeons & Dragons 5e. A character can be viable in a single class from the start of a campaign to the end. This is especially true of the rogue. The rogue is one of the most versatile and capable in all of D&D, but a player might want to multiclass the rogue for several reasons.
Source：https://www.cbr.com/best-rogue-multiclass-combos-dnd/
