Deca and tren will not cancel each other. Both of those compounds are progestins (they activate progesterone receptors). Because of that, they both have side effects that are difficult to control (ED and libido problems, gyno). They are both also difficult to recover from.
Because of the high likelyhood of these side effects and a very difficult post-cycle recovery, most men don't don't want to risk running both compounds in the same cycle.