Right now, you can only use an If/Then statement for a contact being in a pipeline or pipeline stage if an opportunity trigger is used when the contact enters the workflow.
The workflow system basically does not pull opportunity data into the workflow unless an opportunity trigger is used.
This is an unnecessary system limitation and prevents a lot of useful workflows. It makes it so we can’t do even simple things like “tag applied to contact > if contact is in X pipeline > then send contact an email/text” etc.
Please change how workflows work in this manner and cause opportunity data to be pulled into every workflow all the time so we can do actions like this.