I’m not an expert, but I dabble in bonsai so I know a little about trees. It’s probably okay, if it was okay last year. Some trees do not drop all of their dead leaves over the winter. Come spring, some or even most of the dead leaves will still be clinging to the branches.

Trees wake up at slightly different times. Some wake up earlier in the season, some later. Those that wake up later can appear dead for a tie, but they are really fine. You can assess the health of the tree by looking for buds. If buds are swelling on the branches (or starting to open), then the tree is probably fine. It’s just sleeping in. ;-)

Another way to tell if a tree is alive is the scratch test. Find an area where the bark is thin (this could be on a branch) and scratch off a small bit of bark with a fingernail or a small knife. Under the bark is a layer called the cambium. If the part of the tree you scratch is alive, the cambium will appear green. Note that scratching the trunk is a good way to tell if the tree generally is alive, while scratching a branch may only tell you whether that one branch is alive. But on a larger tree, it may not be possible to easily do a scratch test due to the thickness of the bark.