从来 vs 一直

从来 is only used for events in the past, while there is no such restraint for —直.

从来 usually indicates that the event lasts for a long period, which carries a strong tone and even becomes a habit;
—直 indicates that the event lasts for a short period and it may be temporary or recent. Sometimes —直在 is used in that case.

从来 is usually followed by a negative form.
In an affirmative sentence,从来 usually goes with 就，就是，都，都是，etc. However, there is no such restraint for 一直.
Attention: 从来 can be substituted by 从, which must go with a negative form. Eg,我从没见过他。