<div class="form-group">
                <div class="form-inline">
                    <div class="form-group">
                        <label class="sr-only" for="Inputtel">Telefone</label>
                        <input type="tel" class="form-control" id="Inputtel" placeholder="Telefone">
                    </div>
                    <div class="form-group">
                        <label class="sr-only" for="InputCPFCNPJ">CPF ou CNPJ</label>
                        <input type="number" class="form-control" id="InputCPFCNPJ" placeholder="CPF ou CNPJ">
                    </div>
                </div>
            </div>

<div class="form-inline">
                <div class="form-group col-xs-6">
                    <label class="sr-only" for="Inputtel">Telefone</label>
                    <input type="tel" class="form-control" id="Inputtel" placeholder="Telefone">
                </div>
                <div class="form-group col-xs-6">
                    <label class="sr-only" for="InputCPFCNPJ">CPF ou CNPJ</label>
                    <input type="number" class="form-control" id="InputCPFCNPJ" placeholder="CPF ou CNPJ">
                </div>
            </div>

@media (max-width: 767px) {
  .form-inline .form-control {
    display: inline-block;
    width: auto;
    vertical-align: middle;
  }
}
@media (max-width: 767px) {
  .form-inline .form-group {
    display: inline-block;
    margin-bottom: 0;
    vertical-align: middle;
  }
}