Trump has no plan for future operations in Syria because he does not need one yet. This was a one time response to what is likely a one time atrocity by Assad now that he knows Trump will act promptly and decisively, unlike his predecessor. Putin, not being a fool, decided to react with a token response rather than a military response, so Assad now knows who stands where and will do what when provoked. Anyone who still thinks Trump collaborated with the Russians in any way is just being ridiculous.