10. Given the sequences $\left\{a_{n}\right\}$ and $\left\{b_{n}\right\}$ satisfy
$$
\begin{array}{l}
a_{1}=-1, b_{1}=2, \\
a_{n+1}=-b_{n}, b_{n+1}=2 a_{n}-3 b_{n}\left(n \in \mathbf{Z}_{+}\right) .
\end{array}
$$

Then $b_{2015}+b_{2016}=$
10. $-3 \times 2^{2015}$.

From the given $\left\{\begin{array}{l}a_{i+1}=-b_{i}, \\ b_{i+2}=2 a_{i+1}-3 b_{i+1}\end{array}\right.$ we get
$$
\begin{array}{l}
b_{i+2}+b_{i+1}=-2\left(b_{i+1}+b_{i}\right) \\
=(-2)^{2}\left(b_{i}+b_{i-1}\right)=\cdots \\
=(-2)^{i}\left(b_{2}+b_{1}\right) .
\end{array}
$$

Therefore, $b_{2015}+b_{2016}=-3 \times 2^{2015}$.