Kinda. Cancer cells are typically more permissive to viral infection as the innate anti viral pathways tend to get fucked up in cancer cells. So the idea is that the virus will selectively infect cancer cells over healthy cells resulting in less toxicity to your healthy cells (one big problem with many chemotherapeutics). Then the virus may directly kill the cell through lysis or it can induce an immune response which will lead to the immune system clearing the tumor and retaining anti tumor memory (in theory). In practice its much more complex though.

I think oncolytic viruses are insanely promising, especially if combined with antibody based cancer treatments. Jx-594, a variant of the vaccinia virus (was used to vaccinate against small pox) is already fda approved for treating melanoma.